Programs & Examples On #Dll

A dynamic-link library (DLL) is a module that contains functions and data that can be used by another module (application or DLL). It is Microsoft's implementation of the shared library concept in the Microsoft Windows and OS/2 operating systems.

How do I set the path to a DLL file in Visual Studio?

I had the same problem and my problem had nothing to do with paths. One of my dll-s was written in c++ and it turnes out that if your visual studio doesn't know how to open a dll file it will say that it did not find it. What i did was locate which dll it did not find, than searched for that dll in my directories and opened it in a separate visual studio window. When trying to navigate through Solution explorer of that project, visual studio said that it cannot show what is inside and that i need some extra extensions, so that it can open those files. Surely enough, after installing the recomended extension (in my case something to do with c++) the

"This application has failed to start because xxx.dll was not found."

error miraculously dissapeared.

Equivalent to 'app.config' for a library (DLL)

Unfortunately, you can only have one app.config file per executable, so if you have DLL’s linked into your application, they cannot have their own app.config files.

Solution is: You don't need to put the App.config file in the Class Library's project.
You put the App.config file in the application that is referencing your class library's dll.

For example, let's say we have a class library named MyClasses.dll which uses the app.config file like so:

string connect = 

Now, let's say we have an Windows Application named MyApp.exe which references MyClasses.dll. It would contain an App.config with an entry such as:

    <add key="MyClasses.ConnectionString"
         value="Connection string body goes here" />


An xml file is best equivalent for app.config. Use xml serialize/deserialize as needed. You can call it what every you want. If your config is "static" and does not need to change, your could also add it to the project as an embedded resource.

Hope it gives some Idea

How can I use a DLL file from Python?

ctypes will be the easiest thing to use but (mis)using it makes Python subject to crashing. If you are trying to do something quickly, and you are careful, it's great.

I would encourage you to check out Boost Python. Yes, it requires that you write some C++ code and have a C++ compiler, but you don't actually need to learn C++ to use it, and you can get a free (as in beer) C++ compiler from Microsoft.

ImportError: DLL load failed: %1 is not a valid Win32 application. But the DLL's are there

This has worked for me. I have tried different methods but this was my best solution.

Open command prompt and type the following; pip install opencv-python. (make sure your internet is on). after that try importing it again.

Class not registered Error

For me, I had to install Microsoft Access Database Engine 2010 Redistributable and restart my computer.

How can I test a Windows DLL file to determine if it is 32 bit or 64 bit?

A crude way would be to call dumpbin with the headers option from the Visual Studio tools on each DLL and look for the appropriate output:

dumpbin /headers my32bit.dll

PE signature found

File Type: DLL

             14C machine (x86)
               1 number of sections
        45499E0A time date stamp Thu Nov 02 03:28:10 2006
               0 file pointer to symbol table
               0 number of symbols
              E0 size of optional header
            2102 characteristics
                   32 bit word machine

             10B magic # (PE32)

You can see a couple clues in that output that it is a 32 bit DLL, including the 14C value that Paul mentions. Should be easy to look for in a script.

msvcr110.dll is missing from computer error while installing PHP

You need to install the Visual C++ libraries:

As mentioned by Stuart McLaughlin, make sure you get the x86 version even if you use a 64-bits OS because PHP needs some 32-bit libraries.

Where to find "Microsoft.VisualStudio.TestTools.UnitTesting" missing dll?

Simply Refer this URL and download and save required dll files @ this location:

C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE\PublicAssemblies

URL is:

How to view DLL functions?

If a DLL is written in one of the .NET languages and if you only want to view what functions, there is a reference to this DLL in the project.

Then doubleclick the DLL in the references folder and then you will see what functions it has in the OBJECT EXPLORER window

If you would like to view the source code of that DLL file you can use a decompiler application such as .NET reflector. hope this helps you.

DLL References in Visual C++

You need to do a couple of things to use the library:

  1. Make sure that you have both the *.lib and the *.dll from the library you want to use. If you don't have the *.lib, skip #2

  2. Put a reference to the *.lib in the project. Right click the project name in the Solution Explorer and then select Configuration Properties->Linker->Input and put the name of the lib in the Additional Dependencies property.

  3. You have to make sure that VS can find the lib you just added so you have to go to the Tools menu and select Options... Then under Projects and Solutions select VC++ Directories,edit Library Directory option. From within here you can set the directory that contains your new lib by selecting the 'Library Files' in the 'Show Directories For:' drop down box. Just add the path to your lib file in the list of directories. If you dont have a lib you can omit this, but while your here you will also need to set the directory which contains your header files as well under the 'Include Files'. Do it the same way you added the lib.

After doing this you should be good to go and can use your library. If you dont have a lib file you can still use the dll by importing it yourself. During your applications startup you can explicitly load the dll by calling LoadLibrary (see: for more info)



Remember to use #include < Foo.h > as opposed to #include "foo.h". The former searches the include path. The latter uses the local project files.

ActiveX component can't create object

It's also worth checking that you've got "Enable 32-bit Applications" set to True in the advanced settings of the DefaultAppPool within IIS.

Calling functions in a DLL from C++

There are many ways to do this but I think one of the easiest options is to link the application to the DLL at link time and then use a definition file to define the symbols to be exported from the DLL.

CAVEAT: The definition file approach works bests for undecorated symbol names. If you want to export decorated symbols then it is probably better to NOT USE the definition file approach.

Here is an simple example on how this is done.

Step 1: Define the function in the export.h file.

int WINAPI IsolatedFunction(const char *title, const char *test);

Step 2: Define the function in the export.cpp file.

#include <windows.h>

int WINAPI IsolatedFunction(const char *title, const char *test)
    MessageBox(0, title, test, MB_OK);
    return 1;

Step 3: Define the function as an export in the export.def defintion file.

EXPORTS    IsolatedFunction          @1

Step 4: Create a DLL project and add the export.cpp and export.def files to this project. Building this project will create an export.dll and an export.lib file.

The following two steps link to the DLL at link time. If you don't want to define the entry points at link time, ignore the next two steps and use the LoadLibrary and GetProcAddress to load the function entry point at runtime.

Step 5: Create a Test application project to use the dll by adding the export.lib file to the project. Copy the export.dll file to ths same location as the Test console executable.

Step 6: Call the IsolatedFunction function from within the Test application as shown below.

#include "stdafx.h"

// get the function prototype of the imported function
#include "../export/export.h"

int APIENTRY WinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPSTR     lpCmdLine,
                     int       nCmdShow)
    // call the imported function found in the dll
    int result = IsolatedFunction("hello", "world");

    return 0;

Missing `server' JVM (Java\jre7\bin\server\jvm.dll.)

To Fix The "Missing "server" JVM at C:\Program Files\Java\jre7\bin\server\jvm­­.dll, please install or use the JRE or JDK that contains these missing components.

Follow these steps:

Go to and install Java JRE7 (Check if Java 6 is not installed already)

After that, go to C:/Program files/java/jre7/bin

Here, create an folder called Server

Now go into the C:/Program files/java/jre7/bin/client folder

Copy all the data in this folder into the new C:/Program files/java/jre7/bin/Server folder

How to fix PHP Warning: PHP Startup: Unable to load dynamic library 'ext\\php_curl.dll'?

I have the same issue with windows10, apache 2.2.25, php 5.2 Im trying to add GD to a working PHP.

how I turn around and change between forward and backward slash, plus trailing or not, I get some variant of ;

PHP Warning: PHP Startup: Unable to load dynamic library 'C:/php\php_gd2.dll' - Det g\xe5r inte att hitta den angivna modulen.\r\n in Unknown on line 0

(swedish translated: 'It is not possible to find the module' )

in this perticular case, the php.ini was: extension_dir = "C:/php"

the dll is put in two places C:\php and C:\php\ext

IS it possible that there is and "error" in the error log entry ? I.e. that the .dll IS found (as a file) but not of the right format, or something like that ??

How to check for DLL dependency?

NDepend was already mentioned by Jesse (if you analyze .NET code) but let's explain exactly how it can help.

Is there a program/script that can scan an executable for DLL dependencies or execute the program in a "clean" DLL-free environment for testing to prevent these oops situations?

In the NDepend Project Properties panel, you can define what application assemblies to analyze (in green) and NDepend will infer Third-Party assemblies used by application ones (in blue). A list of directories where to search application and third-party assemblies is provided.

NDepend Project Properties Application and Third-Party assemblies

If a third-party assembly is not found in these directories, it will be in error mode. For example, if I remove the .NET Fx directory C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319, I can see that .NET Fx third-party assemblies are not resolved:

NDepend Project Properties Application and Third-Party assemblies not resolved

Disclaimer: I work for NDepend

Merge DLL into EXE?

2019 Update (just for reference):

Starting with .NET Core 3.0, this feature is supported out of the box. To take advantage of the single-file executable publishing, just add the following line to the project configuration file:


Now, dotnet publish should produce a single .exe file without using any external tool.

More documentation for this feature is available at

Embedding DLLs in a compiled executable

.NET Core 3.0 natively supports compiling to a single .exe

The feature is enabled by the usage of the following property in your project file (.csproj):


This is done without any external tool.

See my answer for this question for further details.

How do I resolve "Please make sure that the file is accessible and that it is a valid assembly or COM component"?

Make sure the required dlls are exported (or copied manually) to the bin folder when building your application.

Execute CMD command from code

As mentioned by the other answers you can use:

  Process.Start("notepad somefile.txt");

However, there is another way.

You can instance a Process object and call the Start instance method:

  Process process = new Process();
  process.StartInfo.FileName = "notepad.exe";
  process.StartInfo.WorkingDirectory = "c:\temp";
  process.StartInfo.Arguments = "somefile.txt";

Doing it this way allows you to configure more options before starting the process. The Process object also allows you to retrieve information about the process whilst it is executing and it will give you a notification (via the Exited event) when the process has finished.

Addition: Don't forget to set 'process.EnableRaisingEvents' to 'true' if you want to hook the 'Exited' event.

The module ".dll" was loaded but the entry-point was not found

The error indicates that the DLL is either not a COM DLL or it's corrupt. If it's not a COM DLL and not being used as a COM DLL by an application then there is no need to register it.
From what you say in your question (the service is not registered) it seems that we are talking about a service not correctly installed. I will try to reinstall the application.

Difference between .dll and .exe?

The .exe is the program. The .dll is a library that a .exe (or another .dll) may call into.

What sakthivignesh says can be true in that one .exe can use another as if it were a library, and this is done (for example) with some COM components. In this case, the "slave" .exe is a separate program (strictly speaking, a separate process - perhaps running on a separate machine), but one that accepts and handles requests from other programs/components/whatever.

However, if you just pick a random .exe and .dll from a folder in your Program Files, odds are that COM isn't relevant - they are just a program and its dynamically-linked libraries.

Using Win32 APIs, a program can load and use a DLL using the LoadLibrary and GetProcAddress API functions, IIRC. There were similar functions in Win16.

COM is in many ways an evolution of the DLL idea, originally concieved as the basis for OLE2, whereas .NET is the descendant of COM. DLLs have been around since Windows 1, IIRC. They were originally a way of sharing binary code (particularly system APIs) between multiple running programs in order to minimise memory use.

How do I use a third-party DLL file in Visual Studio C++?

To incorporate third-party DLLs into my VS 2008 C++ project I did the following (you should be able to translate into 2010, 2012 etc.)...

I put the header files in my solution with my other header files, made changes to my code to call the DLLs' functions (otherwise why would we do all this?). :^) Then I changed the build to link the LIB code into my EXE, to copy the DLLs into place, and to clean them up when I did a 'clean' - I explain these changes below.

Suppose you have 2 third-party DLLs, A.DLL and B.DLL, and you have a stub LIB file for each (A.LIB and B.LIB) and header files (A.H and B.H).

  • Create a "lib" directory under your solution directory, e.g. using Windows Explorer.
  • Copy your third-party .LIB and .DLL files into this directory

(You'll have to make the next set of changes once for each source build target that you use (Debug, Release).)

  1. Make your EXE dependent on the LIB files

    • Go to Configuration Properties -> Linker -> Input -> Additional Dependencies, and list your .LIB files there one at a time, separated by spaces: A.LIB B.LIB
    • Go to Configuration Properties -> General -> Additional Library Directories, and add your "lib" directory to any you have there already. Entries are separated by semicolons. For example, if you already had $(SolutionDir)fodder there, you change it to $(SolutionDir)fodder;$(SolutionDir)lib to add "lib".
  2. Force the DLLs to get copied to the output directory

    • Go to Configuration Properties -> Build Events -> Post-Build Event
    • Put the following in for Command Line (for the switch meanings, see "XCOPY /?" in a DOS window):

    XCOPY "$(SolutionDir)"\lib\*.DLL "$(TargetDir)" /D /K /Y

    • You can put something like this for Description:

    Copy DLLs to Target Directory

    • Excluded From Build should be No. Click OK.
  3. Tell VS to clean up the DLLs when it cleans up an output folder:

    • Go to Configuration Properties -> General -> Extensions to Delete on Clean, and click on "..."; add *.dll to the end of the list and click OK.

Loading DLLs at runtime in C#

It's not so difficult.

You can inspect the available functions of the loaded object, and if you find the one you're looking for by name, then snoop its expected parms, if any. If it's the call you're trying to find, then call it using the MethodInfo object's Invoke method.

Another option is to simply build your external objects to an interface, and cast the loaded object to that interface. If successful, call the function natively.

This is pretty simple stuff.

How do I execute a *.dll file

It should be mentioned that since it is entirely possible to run DLL's just as any other executable, it has long been considered a security issue. As such, there have been a number of security improvements and registry hacks (sorry no longer have ref-links) that prevents running DLL's from regular user space without extra privileges.

As a good example. I recall making these hacks, but since I no longer remember what exactly I did. I can no longer run any DLLs from normal user shell environment, even though starting various Win apps from GUI works just fine.

That said, one should definitely read "Dynamic-Link Library Security" and "Best Practices to Prevent DLL Hijacking".

Command line tool to dump Windows DLL version?

Using Powershell it is possible to get just the Version string, i.e. 2.3.4 from any dll or exe with the following command

(Get-Item "C:\program files\OpenVPN\bin\openvpn.exe").VersionInfo.ProductVersion

Tested on Windows 10

How to make Visual Studio copy a DLL file to the output directory?

Add builtin COPY in project.csproj file:

    <Target Name="AfterBuild">
      <Copy SourceFiles="$(ProjectDir)..\..\Lib\*.dll" DestinationFolder="$(OutDir)Debug\bin" SkipUnchangedFiles="false" />
      <Copy SourceFiles="$(ProjectDir)..\..\Lib\*.dll" DestinationFolder="$(OutDir)Release\bin" SkipUnchangedFiles="false" />

what does "error : a nonstatic member reference must be relative to a specific object" mean?

Only static functions are called with class name.


Non static functions have to be called using objects.

classname obj;

This is exactly what your error means. Since your function is non static you have to use a object reference to invoke it.

The program can’t start because MSVCR71.dll is missing from your computer. Try reinstalling the program to fix this program

Agreed with jcadcell comments, but had to use JDK 1.8 because my eclipse need that. So I just copied the MSVCR71.DLL from jdk1.6 and pasted into jdk1.8 in both the folder jdk1.8.0_121\bin and jdk1.8.0_121\jre\bin

and it Worked .... Wow... Thanks :)

Windows 7, 64 bit, DLL problems

This contribution does not really answer the initial question, but taking into account the hit-rate of this thread I assume that there are quite a few people dealing with the problem that API-MS-WIN-CORE- libraries cannot be found.

I was able to solve a problem where my application refused to start with the error message that API-MS-WIN-CORE-WINRT-STRING-L1-1-0.DLL is not found by simply updating Visual Studio.

I don't think that my build environment (Windows 7 Pro SP1, Visual Studio Ultimate 2012) was messed up completely, it worked fine for most of my projects. But under some very specific circumstances I got the error message (see below).

After updating Visual Studio 11 from the initial CD-Version (I forgot to look up the version number) to version 11.0.61030.00 Update 4 also the broken project was running again.

Error message at application startup

How can I specify a [DllImport] path at runtime?

DllImport will work fine without the complete path specified as long as the dll is located somewhere on the system path. You may be able to temporarily add the user's folder to the path.

The name 'ViewBag' does not exist in the current context

I had a ./Views/Web.Config file but this error happened after publishing the site. Turns out the build action property on the file was set to None instead of Content. Changing this to Content allowed publishing to work correctly.

Resolving LNK4098: defaultlib 'MSVCRT' conflicts with

There are 4 versions of the CRT link libraries present in vc\lib:

  • libcmt.lib: static CRT link library for a release build (/MT)
  • libcmtd.lib: static CRT link library for a debug build (/MTd)
  • msvcrt.lib: import library for the release DLL version of the CRT (/MD)
  • msvcrtd.lib: import library for the debug DLL version of the CRT (/MDd)

Look at the linker options, Project + Properties, Linker, Command Line. Note how these libraries are not mentioned here. The linker automatically figures out what /M switch was used by the compiler and which .lib should be linked through a #pragma comment directive. Kinda important, you'd get horrible link errors and hard to diagnose runtime errors if there was a mismatch between the /M option and the .lib you link with.

You'll see the error message you quoted when the linker is told both to link to msvcrt.lib and libcmt.lib. Which will happen if you link code that was compiled with /MT with code that was linked with /MD. There can be only one version of the CRT.

/NODEFAULTLIB tells the linker to ignore the #pragma comment directive that was generated from the /MT compiled code. This might work, although a slew of other linker errors is not uncommon. Things like errno, which is a extern int in the static CRT version but macro-ed to a function in the DLL version. Many others like that.

Well, fix this problem the Right Way, find the .obj or .lib file that you are linking that was compiled with the wrong /M option. If you have no clue then you could find it by grepping the .obj/.lib files for "/MT"

Btw: the Windows executables (like version.dll) have their own CRT version to get their job done. It is located in c:\windows\system32, you cannot reliably use it for your own programs, its CRT headers are not available anywhere. The CRT DLL used by your program has a different name (like msvcrt90.dll).

How do I find the PublicKeyToken for a particular dll?

If you have the DLL added to your project, you can open the csproj file and see the Reference tag.


<Reference Include="System.Web.Mvc, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL" />

Can't load IA 32-bit .dll on a AMD 64-bit platform

Short answer to first question: yes.

Longer answer: maybe; it depends on whether the build process for SVMLight behaves itself on 64-bit windows.

Final note: that call to System.loadLibrary is silly. Either call System.load with a full pathname or let it search java.library.path.

How do I set the version information for an existing .exe, .dll?

the above answer from @DannyBeckett helped me a lot,

I put the following in a batch file & I place it in the same folder where ResourceHacker.exe & the EXE I work on is located & it works excellent. [you may edit it to fit your needs]

    @echo off
    set /p newVersion=Enter version number [?.?.?.?]:
    if "%newVersion%" == "" goto start1
    set /p file=Enter EXE name [for 'program.exe' enter 'program']:
    if "%file%" == "" goto start2
    for /f "tokens=1-4 delims=." %%a in ('echo %newVersion%') do (set ResVersion=%%a,%%b,%%c,%%d)
    echo:    FILEVERSION    %ResVersion%
    echo:    PRODUCTVERSION %ResVersion%
    echo:    BLOCK "StringFileInfo"
    echo:    {
    echo:        BLOCK "040904b0"
    echo:        {
    echo:            VALUE "CompanyName",        "MyCompany\0"
    echo:            VALUE "FileDescription",    "TestFile\0"
    echo:            VALUE "FileVersion",        "%newVersion%\0"
    echo:            VALUE "LegalCopyright",     "COPYRIGHT © 2019 MyCompany\0"
    echo:            VALUE "OriginalFilename",   "%file%.exe\0"
    echo:            VALUE "ProductName",        "Test\0"
    echo:            VALUE "ProductVersion",     "%newVersion%\0"
    echo:        }
    echo:    }
    echo:    BLOCK "VarFileInfo"
    echo:    {
    echo:        VALUE "Translation", 0x409, 1200
    echo:    }
    ) >Resources.rc     &&      echo setting Resources.rc
    ResourceHacker.exe -open resources.rc -save resources.res -action compile -log CONSOLE
    ResourceHacker -open "%file%.exe" -save "%file%Res.exe" -action addoverwrite -resource "resources.res"  -log CONSOLE
    ResourceHacker.exe -open "%file%Res.exe" -save "%file%Ico.exe" -action addskip -res "%file%.ico" -mask ICONGROUP,MAINICON, -log CONSOLE
    xCopy /y /f "%file%Ico.exe" "%file%.exe"
    echo your compiled file %file%.exe is ready

[as a side note i used resource hacker also to compile the res file, not GoRC]

System.MissingMethodException: Method not found?

I solved this problem by making a shelveset with my changes and running TFS Power Tools 'scorch' in my workspace ( Then I unshelved the changes and recompiled the project. This way you will cleanup any 'hanging-parties' that may be around in your workspace and will startup with a fresh one. This requires, of course, that you are using TFS.

When to use dynamic vs. static libraries

A static library gets compiled into the client. A .lib is used at compile time and the contents of the library become part of the consuming executable.

A dynamic library is loaded at runtime and not compiled into the client executable. Dynamic libraries are more flexible as multiple client executables can load a DLL and utilize its functionality. This also keeps the overall size and maintainability of your client code to a minimum.

How do I register a DLL file on Windows 7 64-bit?

If the DLL is 32 bit:

  1. Copy the DLL to C:\Windows\SysWoW64\
  2. In elevated cmd: %windir%\SysWoW64\regsvr32.exe %windir%\SysWoW64\namedll.dll

if the DLL is 64 bit:

  1. Copy the DLL to C:\Windows\System32\
  2. In elevated cmd: %windir%\System32\regsvr32.exe %windir%\System32\namedll.dll

Why do 64-bit DLLs go to System32 and 32-bit DLLs to SysWoW64 on 64-bit Windows?

System32 is where Windows historically placed all 32bit DLLs, and System was for the 16bit DLLs. When microsoft created the 64 bit OS, everyone I know of expected the files to reside under System64, but Microsoft decided it made more sense to put 64bit files under System32. The only reasoning I have been able to find, is that they wanted everything that was 32bit to work in a 64bit Windows w/o having to change anything in the programs -- just recompile, and it's done. The way they solved this, so that 32bit applications could still run, was to create a 32bit windows subsystem called Windows32 On Windows64. As such, the acronym SysWOW64 was created for the System directory of the 32bit subsystem. The Sys is short for System, and WOW64 is short for Windows32OnWindows64.
Since windows 16 is already segregated from Windows 32, there was no need for a Windows 16 On Windows 64 equivalence. Within the 32bit subsystem, when a program goes to use files from the system32 directory, they actually get the files from the SysWOW64 directory. But the process is flawed.

It's a horrible design. And in my experience, I had to do a lot more changes for writing 64bit applications, that simply changing the System32 directory to read System64 would have been a very small change, and one that pre-compiler directives are intended to handle.

How to get the location of the DLL currently executing?


installing JDK8 on Windows XP - advapi32.dll error

This happens because Oracle dropped support for Windows XP (which doesn't have RegDeleteKeyExA used by the installer in its ADVAPI32.DLL by the way) as described in Yet while the official support for XP has ended, the Java binaries are still (as of Java 8u20 EA b05 at least) XP-compatible - only the installer isn't...

Because of that, the solution is actually quite easy:

  1. get 7-Zip (or any other good unpacker), unpack the distribution .exe manually, it has one .zip file inside of it (, extract it too,

  2. use unpack200 from JDK8 to unpack all .pack files to .jar files (older unpacks won't work properly); JAVA_HOME environment variable should be set to your Java unpack root, e.g. "C:\Program Files\Java\jdk8" - you can specify it implicitly by e.g.

    SET JAVA_HOME=C:\Program Files\Java\jdk8
    • Unpack all files with a single command (in batch file):

      FOR /R %%f IN (*.pack) DO "%JAVA_HOME%\bin\unpack200.exe" -r -v "%%f" "%%~pf%%~nf.jar"
    • Unpack all files with a single command (command line from JRE root):

      FOR /R %f IN (*.pack) DO "bin\unpack200.exe" -r -v "%f" "%~pf%~nf.jar"
    • Unpack by manually locating the files and unpacking them one-by-one:

      %JAVA_HOME%\bin\unpack200 -r packname.pack packname.jar

    where packname is for example rt

  3. point the tool you want to use (e.g. Netbeans) to the %JAVA_HOME% and you're good to go.

Note: you probably shouldn't do this just to use Java 8 in your web browser or for any similar reason (installing JRE 8 comes to mind); security flaws in early updates of major Java version releases are (mind me) legendary, and adding to that no real support for neither XP nor Java 8 on XP only makes matters much worse. Not to mention you usually don't need Java in your browser (see e.g. - the topic is already covered on many pages, just Google it if you require further info). In any case, AFAIK the only thing required to apply this procedure to JRE is to change some of the paths specified above from \bin\ to \lib\ (the file placement in installer directory tree is a bit different) - yet I strongly advise against doing it.

See also: How can I get the latest JRE / JDK as a zip file rather than EXE or MSI installer?, JRE 1.7 - java version - returns: java/lang/NoClassDefFoundError: java/lang/Object

The requested operation cannot be performed on a file with a user-mapped section open

I fixed the issue as below:

  1. Restart machine
  2. Delete bin and obj folders from respective project path.
  3. Open visual studio
  4. Clean and build the solution.

There you go issue resolved:)

How do I resolve "Run-time error '429': ActiveX component can't create object"?

The file msrdo20.dll is missing from the installation.

According to the Support Statement for Visual Basic 6.0 on Windows Vista, Windows Server 2008 and Windows 7 this file should be distributed with the application.

I'm not sure why it isn't, but my solution is to place the file somewhere on the machine, and register it using regsvr32 in the command line, eg:

regsvr32 c:\windows\system32\msrdo20.dll

In an ideal world you would package this up with the redistributable.

Register comdlg32.dll gets Regsvr32: DllRegisterServer entry point was not found

SOLUTION OF Regsvr32: DllRegisterServer entry point was not found,

  1. Go to systemdrive(generally c:)\system32 and search file "Regsvr32.exe"
  2. Right click and click in properties and go to security tab and click in advanced button.
  3. Click in owner tab and click edit and select administrators and click ok.
  4. Click in permissions
  5. Click in change permissions.
  6. Choose administrators and click edit and put tick on full control and click ok.
  7. Similarly, choose SYSTEM and edit and put tick on full control and click ok and click in other dialog box which are opened.
  8. Now .dll files can be registered and error don't come, you should re-install any software whose dll files was not registered during installation.

The program can't start because cygwin1.dll is missing... in Eclipse CDT

This error message means that Windows isn't able to find "cygwin1.dll". The Programs that the Cygwin gcc create depend on this DLL. The file is part of cygwin , so most likely it's located in C:\cygwin\bin. To fix the problem all you have to do is add C:\cygwin\bin (or the location where cygwin1.dll can be found) to your system path. Alternatively you can copy cygwin1.dll into your Windows directory.

There is a nice tool called DependencyWalker that you can download from . You can use it to check dependencies of executables, so if you inspect your generated program it tells you which dependencies are missing and which are resolved.

Register DLL file on Windows Server 2008 R2

You need the full path to the regsvr32 so %windir$\system32\regsvr32 <*.dll>

Dependent DLL is not getting copied to the build output folder in Visual Studio

You may set both the main project and ProjectX's build output path to the same folder, then you can get all the dlls you need in that folder.

Unable to load DLL (Module could not be found HRESULT: 0x8007007E)

From what I remember on Windows the search order for a dll is:

  1. Current Directory
  2. System folder, C:\windows\system32 or c:\windows\SysWOW64 (for 32-bit process on 64-bit box).
  3. Reading from the Path environment variable

In addition I'd check the dependencies of the DLL, the dependency walker provided with Visual Studio can help you out here, it can also be downloaded for free:

What exactly are DLL files, and how do they work?

DLL files contain an Export Table which is a list of symbols which can be looked up by the calling program. The symbols are typically functions with the C calling convention (__stcall). The export table also contains the address of the function.

With this information, the calling program can then call the functions within the DLL even though it did not have access to the DLL at compile time.

Introducing Dynamic Link Libraries has some more information.

.Net picking wrong referenced assembly version

If you are experiencing this problem when testing and/or debugging the application from the Visual Studio environment (ASP.NET Development Server), it is necessary to delete all temporary files on the development website folder. To know where that folder is, look for the ASP.NET Development Server icon on the Windows tray icon (it should have a title like this: ASP.NET Development Server - Port ####), right click the icon and select Show Details; thn, the field Physical path will tell you what the temporary folder is, all items there should be deleted to solve the problem. Build and run again the website and the problem should be solved (again, solved for the Development Environment).

Register 32 bit COM DLL to 64 bit Windows 7

To register a comm .dll or .ocx on Windows 7 32-bit, do the following:

Copy .dll or .ocx to c:\windows\system32 Type cmd in Run menu, it will search cmd.exe, right click and click Run as Administrator

It will show a prompt at c:\windows\system32


regsvr32 ocxname.ocx to register .ocx


type regsvr32 dllname.dll to register .dll

What tool can decompile a DLL into C++ source code?

There really isn't any way of doing this as most of the useful information is discarded in the compilation process. However, you may want to take a look at this site to see if you can find some way of extracting something from the DLL.

DLL and LIB files - what and why?

Another aspect is security (obfuscation). Once a piece of code is extracted from the main application and put in a "separated" Dynamic-Link Library, it is easier to attack, analyse (reverse-engineer) the code, since it has been isolated. When the same piece of code is kept in a LIB Library, it is part of the compiled (linked) target application, and this thus harder to isolate (differentiate) that piece of code from the rest of the target binaries.

java.lang.UnsatisfiedLinkError no *****.dll in java.library.path

The original answer by Adam Batkin will lead you to a solution, but if you redeploy your webapp (without restarting your web container), you should run into the following error:

java.lang.UnsatisfiedLinkError: Native Library "foo" already loaded in another classloader
   at java.lang.ClassLoader.loadLibrary0(
   at java.lang.ClassLoader.loadLibrary(
   at java.lang.Runtime.load0(
   at java.lang.System.load(

This happens because the ClassLoader that originally loaded your DLL still references this DLL. However, your webapp is now running with a new ClassLoader, and because the same JVM is running and a JVM won't allow 2 references to the same DLL, you can't reload it. Thus, your webapp can't access the existing DLL and can't load a new one. So.... you're stuck.

Tomcat's ClassLoader documentation outlines why your reloaded webapp runs in a new isolated ClassLoader and how you can work around this limitation (at a very high level).

The solution is to extend Adam Batkin's solution a little:

   package awesome;

   public class Foo {

        static {

        // required to work with JDK 6 and JDK 7
        public static void main(String[] args) {


Then placing a jar containing JUST this compiled class into the TOMCAT_HOME/lib folder.

Now, within your webapp, you just have to force Tomcat to reference this class, which can be done as simply as this:


Now your DLL should be loaded in the common classloader, and can be referenced from your webapp even after being redeployed.

Make sense?

A working reference copy can be found on google code, static-dll-bootstrapper .

dll missing in JDBC

Friends I had the same problem because of the different bit version Make sure following point * Your jdk bit 64 or 32 * Your Path for sqljdbc_4.0\enu\auth\x64 or x86 this directory depend on your jdk bit * sqljdbc_auth.dll select this file based on your bit x64 or x86 and put this in system32 folder and it will works for me

Exporting functions from a DLL with dllexport

For C++ :

I just faced the same issue and I think it is worth mentioning a problem comes up when one use both __stdcall (or WINAPI) and extern "C":

As you know extern "C" removes the decoration so that instead of :

__declspec(dllexport) int Test(void)                        --> dumpbin : ?Test@@YaHXZ

you obtain a symbol name undecorated:

extern "C" __declspec(dllexport) int Test(void)             --> dumpbin : Test

However the _stdcall ( = macro WINAPI, that changes the calling convention) also decorates names so that if we use both we obtain :

   extern "C" __declspec(dllexport) int WINAPI Test(void)   --> dumpbin : _Test@0

and the benefit of extern "C" is lost because the symbol is decorated (with _ @bytes)

Note that this only occurs for x86 architecture because the __stdcall convention is ignored on x64 (msdn : on x64 architectures, by convention, arguments are passed in registers when possible, and subsequent arguments are passed on the stack.).

This is particularly tricky if you are targeting both x86 and x64 platforms.

Two solutions

  1. Use a definition file. But this forces you to maintain the state of the def file.

  2. the simplest way : define the macro (see msdn) :

#define EXPORT comment(linker, "/EXPORT:" __FUNCTION__ "=" __FUNCDNAME__)

and then include the following pragma in the function body:

#pragma EXPORT

Full Example :

 int WINAPI Test(void)
    #pragma EXPORT
    return 1;

This will export the function undecorated for both x86 and x64 targets while preserving the __stdcall convention for x86. The __declspec(dllexport) is not required in this case.

Creating a .dll file in C#.Net

Console Application is an application (.exe), not a Library (.dll). To make a library, create a new project, select "Class Library" in type of project, then copy the logic of your first code into this new project.

Or you can edit the Project Properties and select Class Library instead of Console Application in Output type.

As some code can be "console" dependant, I think first solution is better if you check your logic when you copy it.

Compile a DLL in C/C++, then call it from another program

The thing to watch out for when writing C++ dlls is name mangling. If you want interoperability between C and C++, you'd be better off by exporting non-mangled C-style functions from within the dll.

You have two options to use a dll

  • Either use a lib file to link the symbols -- compile time dynamic linking
  • Use LoadLibrary() or some suitable function to load the library, retrieve a function pointer (GetProcAddress) and call it -- runtime dynamic linking

Exporting classes will not work if you follow the second method though.

How to use Microsoft.Office.Interop.Excel on a machine without installed MS Office?

If the "Customer don't want to install and buy MS Office on a server not at any price", then you cannot use Excel ... But I cannot get the trick: it's all about one basic Office licence which costs something like 150 USD ... And I guess that spending time finding an alternative will cost by far more than this amount!

How do I determine the dependencies of a .NET application?

To browse .NET code dependencies, you can use the capabilities of the tool NDepend. The tool proposes:

For example such query can look like:

from m in Methods 
let depth = m.DepthOfIsUsing("NHibernate.NHibernateUtil.Entity(Type)") 
where depth  >= 0 && m.IsUsing("System.IDisposable")
orderby depth
select new { m, depth }

And its result looks like: (notice the code metric depth, 1 is for direct callers, 2 for callers of direct callers...) (notice also the Export to Graph button to export the query result to a Call Graph)

NDepend dependencies browsing through C# LINQ query

The dependency graph looks like:

NDepend Dependency Graph

The dependency matrix looks like:

NDepend Dependency Matrix

The dependency matrix is de-facto less intuitive than the graph, but it is more suited to browse complex sections of code like:

NDepend Matrix vs Graph

Disclaimer: I work for NDepend

Is there any native DLL export functions viewer?

dumpbin from the Visual Studio command prompt:

dumpbin /exports csp.dll

Example of output:

Microsoft (R) COFF/PE Dumper Version 10.00.30319.01
Copyright (C) Microsoft Corporation.  All rights reserved.

Dump of file csp.dll

File Type: DLL

  Section contains the following exports for CSP.dll

    00000000 characteristics
    3B1D0B77 time date stamp Tue Jun 05 12:40:23 2001
        0.00 version
           1 ordinal base
          25 number of functions
          25 number of names

    ordinal hint RVA      name

          1    0 00001470 CPAcquireContext
          2    1 000014B0 CPCreateHash
          3    2 00001520 CPDecrypt
          4    3 000014B0 CPDeriveKey
          5    4 00001590 CPDestroyHash
          6    5 00001590 CPDestroyKey
          7    6 00001560 CPEncrypt
          8    7 00001520 CPExportKey
          9    8 00001490 CPGenKey
         10    9 000015B0 CPGenRandom
         11    A 000014D0 CPGetHashParam
         12    B 000014D0 CPGetKeyParam
         13    C 00001500 CPGetProvParam
         14    D 000015C0 CPGetUserKey
         15    E 00001580 CPHashData
         16    F 000014F0 CPHashSessionKey
         17   10 00001540 CPImportKey
         18   11 00001590 CPReleaseContext
         19   12 00001580 CPSetHashParam
         20   13 00001580 CPSetKeyParam
         21   14 000014F0 CPSetProvParam
         22   15 00001520 CPSignHash
         23   16 000015A0 CPVerifySignature
         24   17 00001060 DllRegisterServer
         25   18 00001000 DllUnregisterServer


        1000 .data
        1000 .rdata
        1000 .reloc
        1000 .rsrc
        1000 .text

Can't find how to use HttpContent

For JSON Post:

var stringContent = new StringContent(json, Encoding.UTF8, "application/json");
var response = await httpClient.PostAsync("", stringContent);


var stringContent = new FormUrlEncodedContent(new[]
    new KeyValuePair<string, string>("field1", "value1"),
    new KeyValuePair<string, string>("field2", "value2"),
var response = await httpClient.PostAsync("", stringContent);

Dynamically load a function from a DLL

LoadLibrary does not do what you think it does. It loads the DLL into the memory of the current process, but it does not magically import functions defined in it! This wouldn't be possible, as function calls are resolved by the linker at compile time while LoadLibrary is called at runtime (remember that C++ is a statically typed language).

You need a separate WinAPI function to get the address of dynamically loaded functions: GetProcAddress.


#include <windows.h>
#include <iostream>

/* Define a function pointer for our imported
 * function.
 * This reads as "introduce the new type f_funci as the type: 
 *                pointer to a function returning an int and 
 *                taking no arguments.
 * Make sure to use matching calling convention (__cdecl, __stdcall, ...)
 * with the exported function. __stdcall is the convention used by the WinAPI
typedef int (__stdcall *f_funci)();

int main()
  HINSTANCE hGetProcIDDLL = LoadLibrary("C:\\Documents and Settings\\User\\Desktop\\test.dll");

  if (!hGetProcIDDLL) {
    std::cout << "could not load the dynamic library" << std::endl;
    return EXIT_FAILURE;

  // resolve function address here
  f_funci funci = (f_funci)GetProcAddress(hGetProcIDDLL, "funci");
  if (!funci) {
    std::cout << "could not locate the function" << std::endl;
    return EXIT_FAILURE;

  std::cout << "funci() returned " << funci() << std::endl;

  return EXIT_SUCCESS;

Also, you should export your function from the DLL correctly. This can be done like this:

int __declspec(dllexport) __stdcall funci() {
   // ...

As Lundin notes, it's good practice to free the handle to the library if you don't need them it longer. This will cause it to get unloaded if no other process still holds a handle to the same DLL.

How do I get the SQLSRV extension to work with PHP, since MSSQL is deprecated?


The MSSQL extension is not available anymore on Windows with PHP 5.3 or later. SQLSRV, an alternative driver for MS SQL is available from Microsoft: »

Once you downloaded that, follow the instructions at this page:

In a nutshell:

Put the driver file in your PHP extension directory.
Modify the php.ini file to include the driver. For example:


Restart the Web server.

See Also (copied from that page)

The PHP Manual for the SQLSRV extension is located at and offers the following for Installation:

The SQLSRV extension is enabled by adding appropriate DLL file to your PHP extension directory and the corresponding entry to the php.ini file. The SQLSRV download comes with several driver files. Which driver file you use will depend on 3 factors: the PHP version you are using, whether you are using thread-safe or non-thread-safe PHP, and whether your PHP installation was compiled with the VC6 or VC9 compiler. For example, if you are running PHP 5.3, you are using non-thread-safe PHP, and your PHP installation was compiled with the VC9 compiler, you should use the php_sqlsrv_53_nts_vc9.dll file. (You should use a non-thread-safe version compiled with the VC9 compiler if you are using IIS as your web server). If you are running PHP 5.2, you are using thread-safe PHP, and your PHP installation was compiled with the VC6 compiler, you should use the php_sqlsrv_52_ts_vc6.dll file.

The drivers can also be used with PDO.

Difference between shared objects (.so), static libraries (.a), and DLL's (.so)?

You are correct in that static files are copied to the application at link-time, and that shared files are just verified at link time and loaded at runtime.

The dlopen call is not only for shared objects, if the application wishes to do so at runtime on its behalf, otherwise the shared objects are loaded automatically when the application starts. DLLS and .so are the same thing. the dlopen exists to add even more fine-grained dynamic loading abilities for processes. You dont have to use dlopen yourself to open/use the DLLs, that happens too at application startup.

Java Error opening registry key

Uninstall Java (via Control Panel / Programs and Features)

Install Java JRE 7 --> OFFLINE <-- Configure JAVA_HOME and Path = %JAVA_HOME%/bin;%PATH%

WampServer: php-win.exe The program can't start because MSVCR110.dll is missing

As far as I am aware, the MSVCRxxx.dlls are in %SystemRoot%\System32 (usually C:\Windows\System32).

The xxx refers to the version of the MS Visual C Runtime (hence MSVCR...)

However, the complication seems to be that the xxx version is not the same as the two digits of the year "version".

For example, Visual C Runtime 2013 yields MSVCR120.dll and "...Runtime 2012" yields MSVCR110.dll. And then Microsoft packages these as vcredist_x86.exe or vcredist_x64.exe, seemingly irrespective of the xxx version or the Visual Studio version number (2012, 2013 etc) - confused? You have every right to be!

So, firstly, you need to determine whether you need 32 bit, 64 bit or even both (some PHP distributions apparently do need both), then download the relevant vcredist... for the bits AND for the Visual Studio version. As far as I can tell, the only way to tell which vcredist... you have is to start to install it. Recent versions give an intro screen that quotes the Visual Studio version and the xxx version. I have renamed by vcredists to something like vcredist_x64_2012_V11.exe.

[EDIT] Forgot to add earlier that if you are simply looking to "install" the missing DLL (as opposed to resolve some bigger set of issues), then you probably won't do any harm by simply installing the relevant vcredist for your architecture (32 bit, 64 bit) and "missing" version.

Why can't Visual Studio find my DLL?

To add to Oleg's answer:

I was able to find the DLL at runtime by appending Visual Studio's $(ExecutablePath) to the PATH environment variable in Configuration Properties->Debugging. This macro is exactly what's defined in the Configuration Properties->VC++ Directories->Executable Directories field*, so if you have that setup to point to any DLLs you need, simply adding this to your PATH makes finding the DLLs at runtime easy!

* I actually don't know if the $(ExecutablePath) macro uses the project's Executable Directories setting or the global Property Pages' Executable Directories setting. Since I have all of my libraries that I often use configured through the Property Pages, these directories show up as defaults for any new projects I create.

Could not load file or assembly '***.dll' or one of its dependencies

I recently hit this issue, the app would run fine on the developer machines and select others machines but not on recently installed machines. It turned out that the machines it did work on had the Visual C++ 11 Runtime installed while the freshly installed machines didn't. Adding the Visual C++ 11 Runtime redistributable to the app installer fixed the issue...

"This assembly is built by a runtime newer than the currently loaded runtime and cannot be loaded"

Change INSTALL_UTIL_HOME directory from C:\WINDOWS\Microsoft.NET\Framework\v2.0 to C:\WINDOWS\Microsoft.NET\Framework\v4.0.30319 for installing the service. This error mainly occurs for version mismatch.

How do you extract classes' source code from a dll file?

Use Refractor. Download from here.

  1. Open the software after installing.
  2. Press Ctrl + O and select your DLL File.
  3. Dll will be shown in left pane.
  4. Right click on Dll and select Export Source Code.
  5. Select the folder in which you want to export your files
  6. Wait for a while it may take 2-3 minutes

enter image description here

How do I build an import library (.lib) AND a DLL in Visual C++?

you also should specify def name in the project settings here:

Configuration > Properties/Input/Advanced/Module > Definition File

PHP 7: Missing VCRUNTIME140.dll

I had same problem when installing Robot Framework 2.9.2 using the Windows installer version on Windows 7.

I could solve it installing the VC14 builds require to have the "Visual C++ Redistributable for Visual Studio 2015 x86 or x64 installed" from Microsoft website.

What's the shebang/hashbang (#!) in Facebook and new Twitter URLs for?

I always assumed the ! just indicated that the hash fragment that followed corresponded to a URL, with ! taking the place of the site root or domain. It could be anything, in theory, but it seems the Google AJAX Crawling API likes it this way.

The hash, of course, just indicates that no real page reload is occurring, so yes, it’s for AJAX purposes. Edit: Raganwald does a lovely job explaining this in more detail.

Java File - Open A File And Write To It


  • Create a File object that refers to the already existing file on disk.
  • Use a FileWriter object, and use the constructor that takes the File object and a boolean, the latter if true would allow appending text into the File if it exists.
  • Then initialize a PrintWriter passing in the FileWriter into its constructor.
  • Then call println(...) on your PrintWriter, writing your new text into the file.
  • As always, close your resources (the PrintWriter) when you are done with it.
  • As always, don't ignore exceptions but rather catch and handle them.
  • The close() of the PrintWriter should be in the try's finally block.


  PrintWriter pw = null;

  try {
     File file = new File("fubars.txt");
     FileWriter fw = new FileWriter(file, true);
     pw = new PrintWriter(fw);
     pw.println("Fubars rule!");
  } catch (IOException e) {
  } finally {
     if (pw != null) {

Easy, no?

How do you see recent SVN log entries?

To add to what others have said, you could also create an alias in your .bashrc or .bash_aliases file:

alias svnlog='svn log -l 30 | less'

or whatever you want as your default

Is there any way to specify a suggested filename when using data: URI?

Here is a jQuery version based off of Holf's version and works with Chrome and Firefox whereas his version seems to only work with Chrome. It's a little strange to add something to the body to do this but if someone has a better option I'm all for it.

var exportFileName = "export-" + filename;
$('<a></a>', {
    "download": exportFileName,
    "href": "data:," + JSON.stringify(exportData, null,5),
    "id": "exportDataID"

Print to the same line and not a new line?

for object "pega" that provides StartRunning(), StopRunning(), boolean getIsRunning() and integer getProgress100() returning value in range of 0 to 100, this provides text progress bar while running...

now = time.time()
timeout = now + 30.0
last_progress = -1


while now < timeout and pega.getIsRunning():
    now = time.time()

    progress = pega.getTubProgress100()
    if progress != last_progress:
        print('\r'+'='*progress+'-'*(100-progress)+' ' + str(progress) + "% ", end='', flush=True)
        last_progress = progress


progress = pega.getTubProgress100()
print('\r'+'='*progress+'-'*(100-progress)+' ' + str(progress) + "% ", flush=True)

Asp.Net MVC with Drop Down List, and SelectListItem Assistance

Step-1: Your Model class

public class RechargeMobileViewModel
        public string CustomerFullName { get; set; }
        public string TelecomSubscriber { get; set; }
        public int TotalAmount { get; set; }
        public string MobileNumber { get; set; }
        public int Month { get; set; }
        public List<SelectListItem> getAllDaysList { get; set; }

        // Define the list which you have to show in Drop down List
        public List<SelectListItem> getAllWeekDaysList()
            List<SelectListItem> myList = new List<SelectListItem>();
            var data = new[]{
                 new SelectListItem{ Value="1",Text="Monday"},
                 new SelectListItem{ Value="2",Text="Tuesday"},
                 new SelectListItem{ Value="3",Text="Wednesday"},
                 new SelectListItem{ Value="4",Text="Thrusday"},
                 new SelectListItem{ Value="5",Text="Friday"},
                 new SelectListItem{ Value="6",Text="Saturday"},
                 new SelectListItem{ Value="7",Text="Sunday"},
            myList = data.ToList();
            return myList;

Step-2: Call this method to fill Drop down in your controller Action

namespace MvcVariousApplication.Controllers
        public class HomeController : Controller
            public ActionResult Index()
              RechargeMobileViewModel objModel = new RechargeMobileViewModel();
                objModel.getAllDaysList = objModel.getAllWeekDaysList();  
                return View(objModel);

Step-3: Fill your Drop-Down List of View as follows

 @model MvcVariousApplication.Models.RechargeMobileViewModel
        ViewBag.Title = "Contact";
    @Html.LabelFor(model=> model.CustomerFullName)
    @Html.TextBoxFor(model => model.CustomerFullName)

    @Html.LabelFor(model => model.MobileNumber)
    @Html.TextBoxFor(model => model.MobileNumber)

    @Html.LabelFor(model => model.TelecomSubscriber)
    @Html.TextBoxFor(model => model.TelecomSubscriber)

    @Html.LabelFor(model => model.TotalAmount)
    @Html.TextBoxFor(model => model.TotalAmount)

    @Html.LabelFor(model => model.Month)
    @Html.DropDownListFor(model => model.Month, new SelectList(Model.getAllDaysList, "Value", "Text"), "-Select Day-")

In SQL, is UPDATE always faster than DELETE+INSERT?

A bit too late with this answer, but since I faced a similar question, I made a test with JMeter and a MySQL server on same machine, where I have used:

  1. A transaction Controller (generating parent sample) that contained two JDBC Requests: a Delete and an Insert statement
  2. A sepparate JDBC Request containing the Update statement.

After running the test for 500 loops, I have obtained the following results:

DEL + INSERT - Average: 62ms

Update - Average: 30ms

Results: Results

Change background image opacity

There is nothing called background opacity. Opacity is applied to the element, its contents and all its child elements. And this behavior cannot be changed just by overriding the opacity in child elements.

Child vs parent opacity has been a long standing issue and the most common fix for it is using rgba(r,g,b,alpha) background colors. But in this case, since it is a background-image, that solution won't work. One solution would be to generate the image as a PNG with the required opacity in the image itself. Another solution would be to take the child div out and make it absolutely positioned.

How to add items to array in nodejs

var array = [];

//length array now = 0
array[array.length] = 'hello';
//length array now = 1
//            0
//array = ['hello'];//length = 1

Save file to specific folder with curl command

curl doesn't have an option to that (without also specifying the filename), but wget does. The directory can be relative or absolute. Also, the directory will automatically be created if it doesn't exist.

wget -P relative/dir "$url"

wget -P /absolute/dir "$url"

Recursively list all files in a directory including files in symlink directories

The -L option to ls will accomplish what you want. It dereferences symbolic links.

So your command would be:

ls -LR

You can also accomplish this with

find -follow

The -follow option directs find to follow symbolic links to directories.

On Mac OS X use

find -L

as -follow has been deprecated.

How to deal with "java.lang.OutOfMemoryError: Java heap space" error?

If everything else fails, in addition to increasing the max heap size try also increasing the swap size. For Linux, as of now, relevant instructions can be found in

This can help if you're e.g. compiling something big in an embedded platform.

Write HTML file using Java

If you want to do that yourself, without using any external library, a clean way would be to create a template.html file with all the static content, like for example:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" 
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">

Put a tag like $tag for any dynamic content and then do something like this:

File htmlTemplateFile = new File("path/template.html");
String htmlString = FileUtils.readFileToString(htmlTemplateFile);
String title = "New Page";
String body = "This is Body";
htmlString = htmlString.replace("$title", title);
htmlString = htmlString.replace("$body", body);
File newHtmlFile = new File("path/new.html");
FileUtils.writeStringToFile(newHtmlFile, htmlString);

Note: I used for simplicity.

How to close a web page on a button click, a hyperlink or a link button click?

Assuming you're using WinForms, as it was the first thing I did when I was starting C# you need to create an event to close this form.

Lets say you've got a button called myNewButton. If you double click it on WinForms designer you will create an event. After that you just have to use this.Close

    private void myNewButton_Click(object sender, EventArgs e) {

And that should be it.

The only reason for this not working is that your Event is detached from button. But it should create new event if old one is no longer attached when you double click on the button in WinForms designer.

Making authenticated POST requests with Spring RestTemplate for Android

I was recently dealing with an issue when I was trying to get past authentication while making a REST call from Java, and while the answers in this thread (and other threads) helped, there was still a bit of trial and error involved in getting it working.

What worked for me was encoding credentials in Base64 and adding them as Basic Authorization headers. I then added them as an HttpEntity to restTemplate.postForEntity, which gave me the response I needed.

Here's the class I wrote for this in full (extending RestTemplate):

public class AuthorizedRestTemplate extends RestTemplate{

    private String username;
    private String password;

    public AuthorizedRestTemplate(String username, String password){
        this.username = username;
        this.password = password;

    public String getForObject(String url, Object... urlVariables){
        return authorizedRestCall(this, url, urlVariables);

    private String authorizedRestCall(RestTemplate restTemplate, 
            String url, Object... urlVariables){
        HttpEntity<String> request = getRequest();
        ResponseEntity<String> entity = restTemplate.postForEntity(url, 
                request, String.class, urlVariables);
        return entity.getBody();

    private HttpEntity<String> getRequest(){
        HttpHeaders headers = new HttpHeaders();
        headers.add("Authorization", "Basic " + getBase64Credentials());
        return new HttpEntity<String>(headers);

    private String getBase64Credentials(){
        String plainCreds = username + ":" + password;
        byte[] plainCredsBytes = plainCreds.getBytes();
        byte[] base64CredsBytes = Base64.encodeBase64(plainCredsBytes);
        return new String(base64CredsBytes);

Show Current Location and Nearby Places and Route between two places using Google Maps API in Android

Lots of answers so far, which are all excellent pointers to API's and tutorials. One thing I'd like to add is that I work out how far the markers are from my location using something like:

float distance = (float) loc.distanceTo(loc2);

Hope this helps refine the detail for your problem. It returns a rough estimate of distance (in m) between points, and is useful for getting rid of POI that might be too far away - good to declutter your map?

How to force a html5 form validation without submitting it via jQuery

You don't need jQuery to achieve this. In your form add:

onsubmit="return buttonSubmit(this)

or in JavaScript:

myform.setAttribute("onsubmit", "return buttonSubmit(this)");

In your buttonSubmit function (or whatver you call it), you can submit the form using AJAX. buttonSubmit will only get called if your form is validated in HTML5.

In case this helps anyone, here is my buttonSubmit function:

function buttonSubmit(e)
    var ajax;
    var formData = new FormData();
    for (i = 0; i < e.elements.length; i++)
        if (e.elements[i].type == "submit")
            if (submitvalue == e.elements[i].value)
                submit = e.elements[i];
                submit.disabled = true;
        else if (e.elements[i].type == "radio")
            if (e.elements[i].checked)
                formData.append(e.elements[i].name, e.elements[i].value);
            formData.append(e.elements[i].name, e.elements[i].value);
    formData.append("javascript", "javascript");
    var action = e.action;
    status = action.split('/').reverse()[0] + "-status";
    ajax = new XMLHttpRequest();
    ajax.addEventListener("load", manageLoad, false);
    ajax.addEventListener("error", manageError, false);"POST", action);
    return false;

Some of my forms contain multiple submit buttons, hence this line if (submitvalue == e.elements[i].value). I set the value of submitvalue using a click event.

Using routes in Express-js

You could also organise them into modules. So it would be something like.


and then in the indexController.js of the controllers export your controllers.

module.exports = function(){
//do some set up

var self = {
     indexAction : function (req,res){
       //do your thing
return self;

then in index.js of controllers dir

exports.indexController = require("./indexController");

and finally in app.js

var controllers = require("./controllers");


I think this approach allows for clearer seperation and also you can configure your controllers by passing perhaps a db connection in.

C++ "was not declared in this scope" compile error

grid is not present on nonrecursivecountcells's scope.

Either make grid a global array, or pass it as a parameter to the function.

Converting String to Double in Android

    cost=(TextView )findViewById(;

            btn.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) { cst =  Double.valueOf(kw.getText().toString());
            cst = cst*0.551;

Jquery mouseenter() vs mouseover()

This example demonstrates the difference between the mousemove, mouseenter and mouseover events:


<div onmousemove="myMoveFunction()">
    <p>onmousemove: <br> <span id="demo">Mouse over me!</span></p>

<div onmouseenter="myEnterFunction()">
    <p>onmouseenter: <br> <span id="demo2">Mouse over me!</span></p>

<div onmouseover="myOverFunction()">
    <p>onmouseover: <br> <span id="demo3">Mouse over me!</span></p>


div {
    width: 200px;
    height: 100px;
    border: 1px solid black;
    margin: 10px;
    float: left;
    padding: 30px;
    text-align: center;
    background-color: lightgray;

p {
    background-color: white;
    height: 50px;

p span {
    background-color: #86fcd4;
    padding: 0 20px;


var x = 0;
var y = 0;
var z = 0;

function myMoveFunction() {
    document.getElementById("demo").innerHTML = z += 1;

function myEnterFunction() {
    document.getElementById("demo2").innerHTML = x += 1;

function myOverFunction() {
    document.getElementById("demo3").innerHTML = y += 1;
  • onmousemove : occurs every time the mouse pointer is moved over the div element.
  • onmouseenter : only occurs when the mouse pointer enters the div element.
  • onmouseover : occurs when the mouse pointer enters the div element, and its child elements (p and span).

How to remove folders with a certain name

Combining multiple answers, here's a command that works on both Linux and MacOS

rm -rf $(find . -type d -name __pycache__)

how to return a char array from a function in C

Daniel is right:





Also, you need to forward declare substring:

char *substring(int i,int j,char *ch);

int main // ...

How to show all privileges from a user in oracle?

You can use below code to get all the privileges list from all users.

select * from dba_sys_privs 

Default interface methods are only supported starting with Android N

This also happened to me but using Dynamic Features. I already had Java 8 compatibility enabled in the app module but I had to add this compatibility lines to the Dynamic Feature module and then it worked.

Change the current directory from a Bash script

In light of the unreadability and overcomplication of answers, i believe this is what the requestor should do

  1. add that script to the PATH
  2. run the script as . scriptname

The . (dot) will make sure the script is not run in a child shell.

WARNING: Setting property 'source' to 'org.eclipse.jst.jee.server:appname' did not find a matching property

You can change the eclipse tomcat server configuration. Open the server view, double click on you server to open server configuration. Then click to activate "Publish module contents to separate XML files". Finally, restart your server, the message must disappear.


What are the basic rules and idioms for operator overloading?

Common operators to overload

Most of the work in overloading operators is boiler-plate code. That is little wonder, since operators are merely syntactic sugar, their actual work could be done by (and often is forwarded to) plain functions. But it is important that you get this boiler-plate code right. If you fail, either your operator’s code won’t compile or your users’ code won’t compile or your users’ code will behave surprisingly.

Assignment Operator

There's a lot to be said about assignment. However, most of it has already been said in GMan's famous Copy-And-Swap FAQ, so I'll skip most of it here, only listing the perfect assignment operator for reference:

X& X::operator=(X rhs)
  return *this;

Bitshift Operators (used for Stream I/O)

The bitshift operators << and >>, although still used in hardware interfacing for the bit-manipulation functions they inherit from C, have become more prevalent as overloaded stream input and output operators in most applications. For guidance overloading as bit-manipulation operators, see the section below on Binary Arithmetic Operators. For implementing your own custom format and parsing logic when your object is used with iostreams, continue.

The stream operators, among the most commonly overloaded operators, are binary infix operators for which the syntax specifies no restriction on whether they should be members or non-members. Since they change their left argument (they alter the stream’s state), they should, according to the rules of thumb, be implemented as members of their left operand’s type. However, their left operands are streams from the standard library, and while most of the stream output and input operators defined by the standard library are indeed defined as members of the stream classes, when you implement output and input operations for your own types, you cannot change the standard library’s stream types. That’s why you need to implement these operators for your own types as non-member functions. The canonical forms of the two are these:

std::ostream& operator<<(std::ostream& os, const T& obj)
  // write obj to stream

  return os;

std::istream& operator>>(std::istream& is, T& obj)
  // read obj from stream

  if( /* no valid object of T found in stream */ )

  return is;

When implementing operator>>, manually setting the stream’s state is only necessary when the reading itself succeeded, but the result is not what would be expected.

Function call operator

The function call operator, used to create function objects, also known as functors, must be defined as a member function, so it always has the implicit this argument of member functions. Other than this, it can be overloaded to take any number of additional arguments, including zero.

Here's an example of the syntax:

class foo {
    // Overloaded call operator
    int operator()(const std::string& y) {
        // ...


foo f;
int a = f("hello");

Throughout the C++ standard library, function objects are always copied. Your own function objects should therefore be cheap to copy. If a function object absolutely needs to use data which is expensive to copy, it is better to store that data elsewhere and have the function object refer to it.

Comparison operators

The binary infix comparison operators should, according to the rules of thumb, be implemented as non-member functions1. The unary prefix negation ! should (according to the same rules) be implemented as a member function. (but it is usually not a good idea to overload it.)

The standard library’s algorithms (e.g. std::sort()) and types (e.g. std::map) will always only expect operator< to be present. However, the users of your type will expect all the other operators to be present, too, so if you define operator<, be sure to follow the third fundamental rule of operator overloading and also define all the other boolean comparison operators. The canonical way to implement them is this:

inline bool operator==(const X& lhs, const X& rhs){ /* do actual comparison */ }
inline bool operator!=(const X& lhs, const X& rhs){return !operator==(lhs,rhs);}
inline bool operator< (const X& lhs, const X& rhs){ /* do actual comparison */ }
inline bool operator> (const X& lhs, const X& rhs){return  operator< (rhs,lhs);}
inline bool operator<=(const X& lhs, const X& rhs){return !operator> (lhs,rhs);}
inline bool operator>=(const X& lhs, const X& rhs){return !operator< (lhs,rhs);}

The important thing to note here is that only two of these operators actually do anything, the others are just forwarding their arguments to either of these two to do the actual work.

The syntax for overloading the remaining binary boolean operators (||, &&) follows the rules of the comparison operators. However, it is very unlikely that you would find a reasonable use case for these2.

1 As with all rules of thumb, sometimes there might be reasons to break this one, too. If so, do not forget that the left-hand operand of the binary comparison operators, which for member functions will be *this, needs to be const, too. So a comparison operator implemented as a member function would have to have this signature:

bool operator<(const X& rhs) const { /* do actual comparison with *this */ }

(Note the const at the end.)

2 It should be noted that the built-in version of || and && use shortcut semantics. While the user defined ones (because they are syntactic sugar for method calls) do not use shortcut semantics. User will expect these operators to have shortcut semantics, and their code may depend on it, Therefore it is highly advised NEVER to define them.

Arithmetic Operators

Unary arithmetic operators

The unary increment and decrement operators come in both prefix and postfix flavor. To tell one from the other, the postfix variants take an additional dummy int argument. If you overload increment or decrement, be sure to always implement both prefix and postfix versions. Here is the canonical implementation of increment, decrement follows the same rules:

class X {
  X& operator++()
    // do actual increment
    return *this;
  X operator++(int)
    X tmp(*this);
    return tmp;

Note that the postfix variant is implemented in terms of prefix. Also note that postfix does an extra copy.2

Overloading unary minus and plus is not very common and probably best avoided. If needed, they should probably be overloaded as member functions.

2 Also note that the postfix variant does more work and is therefore less efficient to use than the prefix variant. This is a good reason to generally prefer prefix increment over postfix increment. While compilers can usually optimize away the additional work of postfix increment for built-in types, they might not be able to do the same for user-defined types (which could be something as innocently looking as a list iterator). Once you got used to do i++, it becomes very hard to remember to do ++i instead when i is not of a built-in type (plus you'd have to change code when changing a type), so it is better to make a habit of always using prefix increment, unless postfix is explicitly needed.

Binary arithmetic operators

For the binary arithmetic operators, do not forget to obey the third basic rule operator overloading: If you provide +, also provide +=, if you provide -, do not omit -=, etc. Andrew Koenig is said to have been the first to observe that the compound assignment operators can be used as a base for their non-compound counterparts. That is, operator + is implemented in terms of +=, - is implemented in terms of -= etc.

According to our rules of thumb, + and its companions should be non-members, while their compound assignment counterparts (+= etc.), changing their left argument, should be a member. Here is the exemplary code for += and +; the other binary arithmetic operators should be implemented in the same way:

class X {
  X& operator+=(const X& rhs)
    // actual addition of rhs to *this
    return *this;
inline X operator+(X lhs, const X& rhs)
  lhs += rhs;
  return lhs;

operator+= returns its result per reference, while operator+ returns a copy of its result. Of course, returning a reference is usually more efficient than returning a copy, but in the case of operator+, there is no way around the copying. When you write a + b, you expect the result to be a new value, which is why operator+ has to return a new value.3 Also note that operator+ takes its left operand by copy rather than by const reference. The reason for this is the same as the reason giving for operator= taking its argument per copy.

The bit manipulation operators ~ & | ^ << >> should be implemented in the same way as the arithmetic operators. However, (except for overloading << and >> for output and input) there are very few reasonable use cases for overloading these.

3 Again, the lesson to be taken from this is that a += b is, in general, more efficient than a + b and should be preferred if possible.

Array Subscripting

The array subscript operator is a binary operator which must be implemented as a class member. It is used for container-like types that allow access to their data elements by a key. The canonical form of providing these is this:

class X {
        value_type& operator[](index_type idx);
  const value_type& operator[](index_type idx) const;
  // ...

Unless you do not want users of your class to be able to change data elements returned by operator[] (in which case you can omit the non-const variant), you should always provide both variants of the operator.

If value_type is known to refer to a built-in type, the const variant of the operator should better return a copy instead of a const reference:

class X {
  value_type& operator[](index_type idx);
  value_type  operator[](index_type idx) const;
  // ...

Operators for Pointer-like Types

For defining your own iterators or smart pointers, you have to overload the unary prefix dereference operator * and the binary infix pointer member access operator ->:

class my_ptr {
        value_type& operator*();
  const value_type& operator*() const;
        value_type* operator->();
  const value_type* operator->() const;

Note that these, too, will almost always need both a const and a non-const version. For the -> operator, if value_type is of class (or struct or union) type, another operator->() is called recursively, until an operator->() returns a value of non-class type.

The unary address-of operator should never be overloaded.

For operator->*() see this question. It's rarely used and thus rarely ever overloaded. In fact, even iterators do not overload it.

Continue to Conversion Operators

Difference between id and name attributes in HTML

ID is used to uniquely identify an element.

Name is used in forms.Although you submit a form, if you dont give any name, nothing will will be submitted. Hence form elements need a name to get identified by form methods like "get or push".

And the ones only with name attribute will go out.

How to do multiple conditions for single If statement

Use the 'And' keyword for a logical and. Like this:

If Not ((filename = testFileName) And (fileName <> "")) Then

How to add /usr/local/bin in $PATH on Mac

To make the edited value of path persists in the next sessions

cd ~/
touch .bash_profile
open .bash_profile

That will open the .bash_profile in editor, write inside the following after adding what you want to the path separating each value by column.

export PATH=$PATH:/usr/local/git/bin:/usr/local/bin:

Save, exit, restart your terminal and enjoy

Questions every good PHP Developer should be able to answer

What is wrong with the following code?

$a = 2;
function foo()
    $a = 3;
echo $a;

No more data to read from socket error

I got this error then restarted my GlassFish server that held connection pools between my client app and the database, and the error went away. So, try restarting your application server if applicable.

Excel VBA Check if directory exists error

I ended up using:

Function DirectoryExists(Directory As String) As Boolean
    DirectoryExists = False
    If Len(Dir(Directory, vbDirectory)) > 0 Then
        If (GetAttr(Directory) And vbDirectory) = vbDirectory Then
            DirectoryExists = True
        End If
    End If
End Function

which is a mix of @Brian and @ZygD answers. Where I think @Brian's answer is not enough and don't like the On Error Resume Next used in @ZygD's answer

Tuple unpacking in for loops

Short answer, unpacking tuples from a list in a for loop works. enumerate() creates a tuple using the current index and the entire current item, such as (0, ('bob', 3))

I created some test code to demonstrate this:

    list = [('bob', 3), ('alice', 0), ('john', 5), ('chris', 4), ('alex', 2)]

    print("Displaying Enumerated List")
    for name, num in enumerate(list):
        print("{0}: {1}".format(name, num))

    print("Display Normal Iteration though List")
    for name, num in list:
        print("{0}: {1}".format(name, num))

The simplicity of Tuple unpacking is probably one of my favourite things about Python :D

Eclipse - Failed to load class "org.slf4j.impl.StaticLoggerBinder"

Did you update the project (right-click on the project, "Maven" > "Update project...")? Otherwise, you need to check if pom.xml contains the necessary slf4j dependencies, e.g.:


Make Div overlay ENTIRE page (not just viewport)?

First of all, I think you've misunderstood what the viewport is. The viewport is the area a browser uses to render web pages, and you cannot in any way build your web sites to override this area in any way.

Secondly, it seems that the reason that your overlay-div won't cover the entire viewport is because you have to remove all margins on BODY and HTML.

Try adding this at the top of your stylesheet - it resets all margins and paddings on all elements. Makes further development easier:

* { margin: 0; padding: 0; }

Edit: I just understood your question better. Position: fixed; will probably work out for you, as Jonathan Sampson have written.

Search for highest key/index in an array

$keys = array_keys($arr);
$keys = rsort($keys);

print $keys[0];

should print "10"

docker : invalid reference format

In powershell you should use ${pwd} vs $(pwd)

Best practice to look up Java Enum

Looks like you have a bad practice here but not where you think.

Catching an IllegalArgumentException to rethrow another RuntimeException with a clearer message might look like a good idea but it is not. Because it means you care about messages in your exceptions.

If you care about messages in your exceptions, then it means that your user is somehow seeing your exceptions. This is bad.

If you want to provide an explicit error message to your user, you should check the validity of the enum value when parsing user input and send the appropriate error message in the response if user input is incorrect.

Something like:

// This code uses pure fantasy, you are warned!
class MyApi
    // Return the 24-hour from a 12-hour and AM/PM

    void getHour24(Request request, Response response)
        // validate user input
        int nTime12 = 1;
            nTime12 = Integer.parseInt(request.getParam("hour12"));
            if( nTime12 <= 0 || nTime12 > 12 )
                throw new NumberFormatException();
        catch( NumberFormatException e )
            response.setCode(400); // Bad request
            response.setContent("time12 must be an integer between 1 and 12");

        AMPM pm = null;
            pm = AMPM.lookup(request.getParam("pm"));
        catch( IllegalArgumentException e )
            response.setCode(400); // Bad request
            response.setContent("pm must be one of " + AMPM.values());

        switch( pm )
            case AM:
            case PM:
                response.setContent(nTime12 + 12);

What does .pack() do?

The pack() method is defined in Window class in Java and it sizes the frame so that all its contents are at or above their preferred sizes.

How do I check if an object's type is a particular subclass in C++?

I was thinking along the lines of using typeid()...

Well, yes, it could be done by comparing: typeid().name(). If we take the already described situation, where:

class Base;
class A : public Base {...};
class B : public Base {...};

void foo(Base *p)
  if(/* p is A */) /* do X */
  else /* do Y */

A possible implementation of foo(Base *p) would be:

#include <typeinfo>

void foo(Base *p)
    if(typeid(*p) == typeid(A))
        // the pointer is pointing to the derived class A
    else if (typeid(*p).name() == typeid(B).name()) 
        // the pointer is pointing to the derived class B

How to hide column of DataGridView when using custom DataSource?

I have noticed that if utilised progrmmatically it renders incomplete (entire form simply doesn't "paint" anything) if used before panel1.Controls.Add(dataGridView); then dataGridView.Columns["ID"].Visible = false; will break the entire form and make it blank, so to get round that set this AFTER EG:

 dataGridView.Columns["ID"].Visible = false; 

 dataGridView.Columns["ID"].Visible = false; 
 //fails miserably

Remove final character from string


st =  "abcdefghij"
st = st[:-1]

There is also another way that shows how it is done with steps:

list1 = "abcdefghij"
list2 = list(list1)
list3 = list2[:-1]

This is also a way with user input:

list1 = input ("Enter :")
list2 = list(list1)
list3 = list2[:-1]

To make it take away the last word in a list:

list1 = input("Enter :")
list2 = list1.split()
list3 = list2[:-1]

Force LF eol in git repo and working copy

To force LF line endings for all text files, you can create .gitattributes file in top-level of your repository with the following lines (change as desired):

# Ensure all C and PHP files use LF.
*.c         eol=lf
*.php       eol=lf

which ensures that all files that Git considers to be text files have normalized (LF) line endings in the repository (normally core.eol configuration controls which one do you have by default).

Based on the new attribute settings, any text files containing CRLFs should be normalized by Git. If this won't happen automatically, you can refresh a repository manually after changing line endings, so you can re-scan and commit the working directory by the following steps (given clean working directory):

$ echo "* text=auto" >> .gitattributes
$ rm .git/index     # Remove the index to force Git to
$ git reset         # re-scan the working directory
$ git status        # Show files that will be normalized
$ git add -u
$ git add .gitattributes
$ git commit -m "Introduce end-of-line normalization"

or as per GitHub docs:

git add . -u
git commit -m "Saving files before refreshing line endings"
git rm --cached -r . # Remove every file from Git's index.
git reset --hard # Rewrite the Git index to pick up all the new line endings.
git add . # Add all your changed files back, and prepare them for a commit.
git commit -m "Normalize all the line endings" # Commit the changes to your repository.

See also: @Charles Bailey post.

In addition, if you would like to exclude any files to not being treated as a text, unset their text attribute, e.g.

manual.pdf      -text

Or mark it explicitly as binary:

# Denote all files that are truly binary and should not be modified.
*.png binary
*.jpg binary

To see some more advanced git normalization file, check .gitattributes at Drupal core:

# Drupal git normalization
# @see
# @see

# Normally these settings would be done with macro attributes for improved
# readability and easier maintenance. However macros can only be defined at the
# repository root directory. Drupal avoids making any assumptions about where it
# is installed.

# Define text file attributes.
# - Treat them as text.
# - Ensure no CRLF line-endings, neither on checkout nor on checkin.
# - Detect whitespace errors.
#   - Exposed by default in `git diff --color` on the CLI.
#   - Validate with `git diff --check`.
#   - Deny applying with `git apply --whitespace=error-all`.
#   - Fix automatically with `git apply --whitespace=fix`.

*.config  text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.css     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.dist    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.engine  text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.html    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=html
*.inc     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.install text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.js      text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.json    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.lock    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.map     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.md      text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.module  text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.php     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.po      text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.profile text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.script  text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.sh      text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.sql     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.svg     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.theme   text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2 diff=php
*.twig    text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.txt     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.xml     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
*.yml     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2

# Define binary file attributes.
# - Do not treat them as text.
# - Include binary diff in patches instead of "binary files differ."
*.eot     -text diff
*.exe     -text diff
*.gif     -text diff
*.gz      -text diff
*.ico     -text diff
*.jpeg    -text diff
*.jpg     -text diff
*.otf     -text diff
*.phar    -text diff
*.png     -text diff
*.svgz    -text diff
*.ttf     -text diff
*.woff    -text diff
*.woff2   -text diff

See also:

Can a div have multiple classes (Twitter Bootstrap)

You can add as many classes to an element, but you can add only one id per element.

<div id="unique" class="class1 class2 class3 class4"></div>

How to ping a server only once from within a batch file?

Just write the command "ping your server IP" without the double quote. save file name as filename.bat and then run the batch file as administrator

How to scale an Image in ImageView to keep the aspect ratio

This worked for me:

android:adjustViewBounds ="true"

App can't be opened because it is from an unidentified developer

you can modify the gatekeeper settings by running the following command

To disable to allow apps from anywhere to be installed use the following command in terminal ::

sudo spctl --master-disable

To re-enable use the following command

sudo spctl --master-enable

Uploading images using Node.js, Express, and Mongoose

Here's a way to upload your images using the formidable package, which is recommended over bodyParser in later versions of Express. This also includes the ability to resize your images on the fly:

From my website: Uploading and Resizing Images (on the fly) With Node.js and Express.

Here's the gist:

var express = require("express"),
app = express(),
formidable = require('formidable'),
util = require('util')
fs   = require('fs-extra'),
qt   = require('quickthumb');

// Use quickthumb
app.use(qt.static(__dirname + '/'));'/upload', function (req, res){
  var form = new formidable.IncomingForm();
  form.parse(req, function(err, fields, files) {
    res.writeHead(200, {'content-type': 'text/plain'});
    res.write('received upload:\n\n');
    res.end(util.inspect({fields: fields, files: files}));

  form.on('end', function(fields, files) {
    /* Temporary location of our uploaded file */
    var temp_path = this.openedFiles[0].path;
    /* The file name of the uploaded file */
    var file_name = this.openedFiles[0].name;
    /* Location where we want to copy the uploaded file */
    var new_location = 'uploads/';

    fs.copy(temp_path, new_location + file_name, function(err) {  
      if (err) {
      } else {

// Show the upload form 
app.get('/', function (req, res){
  res.writeHead(200, {'Content-Type': 'text/html' });
  /* Display the file upload form. */
  form = '<form action="/upload" enctype="multipart/form-data" method="post">'+ '<input name="title" type="text" />
  '+ '<input multiple="multiple" name="upload" type="file" />
  '+ '<input type="submit" value="Upload" />'+ '</form>';

NOTE: This requires Image Magick for the quick thumb resizing.

How to use group by with union in t-sql

with UnionTable as  
    SELECT, a.time FROM dbo.a
    SELECT, b.time FROM dbo.b
) SELECT id FROM UnionTable GROUP BY id

Javascript call() & apply() vs bind()?

Call: call invokes the function and allows you to pass arguments one by one

Apply: Apply invokes the function and allows you to pass arguments as an array

Bind: Bind returns a new function, allowing you to pass in a this array and any number of arguments.

var person1 = {firstName: 'Raju', lastName: 'king'};_x000D_
var person2 = {firstName: 'chandu', lastName: 'shekar'};_x000D_
function greet(greeting) {_x000D_
    console.log(greeting + ' ' + this.firstName + ' ' + this.lastName);_x000D_
function greet2(greeting) {_x000D_
        console.log( 'Hello ' + this.firstName + ' ' + this.lastName);_x000D_
_x000D_, 'Hello'); // Hello Raju king_x000D_, 'Hello'); // Hello chandu shekar_x000D_
greet.apply(person1, ['Hello']); // Hello Raju king_x000D_
greet.apply(person2, ['Hello']); // Hello chandu shekar_x000D_
var greetRaju = greet2.bind(person1);_x000D_
var greetChandu = greet2.bind(person2);_x000D_
greetRaju(); // Hello Raju king_x000D_
greetChandu(); // Hello chandu shekar

BadImageFormatException. This will occur when running in 64 bit mode with the 32 bit Oracle client components installed

I would like to add a resolution that worked for me. Setup: Oracle 11g 64 bits running on Windows 2008 R2 (64 bits OS)

Client is a .net framework 3.5 application (ported from 2.0) compiled with x86 platform setting.

I had the exact same issue of BadImageFormatException. Compiling to 64 bits eliminates the exception but it was not an option for me as my app is using 32 bits activex components who do not work in 64 bits.

I solved the issue by downloading Oracle Instant Client 11 (this is just a bunch of DLL than can be xcopied) from Oracle website, and copying the files in my application files directory. See here :

This has solved the issue, from ProcMon tool I can see that the locally copied oci.dll gets loaded by System.Data.OracleClient and everything is fine.

It could probably be done by changing environment settings like proposed above, but this method has the advantage of not altering any settings on the server configuration.


MySQL will assume the part before the equals references the columns named in the INSERT INTO clause, and the second part references the SELECT columns.

INSERT INTO lee(exp_id, created_by, location, animal, starttime, endtime, entct, 
                inact, inadur, inadist, 
                smlct, smldur, smldist, 
                larct, lardur, lardist, 
                emptyct, emptydur)
SELECT id, uid, t.location, t.animal, t.starttime, t.endtime, t.entct, 
       t.inact, t.inadur, t.inadist, 
       t.smlct, t.smldur, t.smldist, 
       t.larct, t.lardur, t.lardist, 
       t.emptyct, t.emptydur 
FROM tmp t WHERE uid=x
ON DUPLICATE KEY UPDATE entct=t.entct, inact=t.inact, ...

Stack array using pop() and push()

Stack Implementation in Java

  class stack
  {  private int top;
     private int[] element;
      {element=new int[10];
      void push(int item)


      void pop()
      void display()

      public static void main(String args[])
        stack s1=new stack();



Top=0 Element=10 Top=1 Element=20 Top=2 Element=30 Top=1 Element=20

SQL How to replace values of select return?

I got the solution

   CASE status
      WHEN 'VS' THEN 'validated by subsidiary'
      WHEN 'NA' THEN 'not acceptable'
      WHEN 'D'  THEN 'delisted'
      ELSE 'validated'

This is using the CASE This is another to manipulate the selected value for more that two options.

Which passwordchar shows a black dot (•) in a winforms textbox?

One more solution to use this Unicode black circle >>

Start >> All Programs >> Accessories >> System Tools >> Character Map

Then select Arial font and choose the Black circle copy it and paste it into PasswordChar property of the textbox.

That's it....

Transparent ARGB hex value

If you have your hex value, and your just wondering what the value for the alpha would be, this snippet may help:

const alphaToHex = (alpha => {_x000D_
  if (alpha > 1 || alpha < 0 || isNaN(alpha)) {_x000D_
    throw new Error('The argument must be a number between 0 and 1');_x000D_
  return Math.ceil(255 * alpha).toString(16).toUpperCase();_x000D_

HTML img align="middle" doesn't align an image

How about this? I frequently use the CSS Flexible Box Layout to center something.

<div style="display: flex; justify-content: center;">_x000D_
  <img src="" style="width: 40px; height: 40px;" />_x000D_

Which browser has the best support for HTML 5 currently?

i think right now is Firefox 3.6.2, but when internet explorer 9 launched, it will support HTML5

How to add a button to UINavigationBar?

swift 3

    let cancelBarButton = UIBarButtonItem(title: "Cancel", style: .done, target: self, action: #selector(cancelPressed(_:)))
    cancelBarButton.setTitleTextAttributes( [NSFontAttributeName : UIFont.cancelBarButtonFont(),
                                                          NSForegroundColorAttributeName : UIColor.white], for: .normal)
    self.navigationItem.leftBarButtonItem = cancelBarButton

    func cancelPressed(_ sender: UIBarButtonItem ) {
        self.dismiss(animated: true, completion: nil)

Effective swapping of elements of an array in Java

Incredibly late to the party (my apologies) but a more generic solution than those provided here can be implemented (will work with primitives and non-primitives alike):

public static void swap(final Object array, final int i, final int j) {
    final Object atI = Array.get(array, i);
    Array.set(array, i, Array.get(array, j));
    Array.set(array, j, atI);

You lose compile-time safety, but it should do the trick.

Note I: You'll get a NullPointerException if the given array is null, an IllegalArgumentException if the given array is not an array, and an ArrayIndexOutOfBoundsException if either of the indices aren't valid for the given array.

Note II: Having separate methods for this for every array type (Object[] and all primitive types) would be more performant (using the other approaches given here) since this requires some boxing/unboxing. But it'd also be a whole lot more code to write/maintain.

CSS Classes & SubClasses

FYI, when you define a rule like you did above, with two selectors chained together:


It means:

Apply this style to any element that has both the class "area1" and "item".

Such as:

<div class="area1 item">

Sadly it doesn't work in IE6, but that's what it means.

Facebook page automatic "like" URL (for QR Code)

For a hyperlink just use ID++/like


To make it work with here's what you do:

Open the Facebook page you're looking for then change the URL to the mobile URL ( which is ).

Now you should see a big version of the mobile Facebook page. Copy the target URL of the like button.

Pop that URL into the QR generator to make a "scan to like" barcode. This will open the m.Facebook page in the browser of most mobiles directly from the QR reader. If they are not logged into Facebook then they will be prompted to log in and then click 'like'. If logged in, it will auto like.

Hope this helps!

Also, definitely include something with a "click here/scan here to like us on Facebook"

Get the cartesian product of a series of lists?


Available from Python 2.6.

import itertools

somelists = [
   [1, 2, 3],
   ['a', 'b'],
   [4, 5]
for element in itertools.product(*somelists):

Which is the same as,

for element in itertools.product([1, 2, 3], ['a', 'b'], [4, 5]):

Format date and time in a Windows batch script

There is another easy way of doing it:

set HH=%time:~0,2%
if %HH% LEQ 9 (
set HH=%time:~1,1%

How to make a TextBox accept only alphabetic characters?

This one is working absolutely fine...

 private void manufacturerOrSupplierTextBox_KeyPress(object sender, KeyPressEventArgs e)
        if (char.IsControl(e.KeyChar) || char.IsLetter(e.KeyChar))
        e.Handled = true;

Sample database for exercise

You want huge?

Here's a small table: create table foo (id int not null primary key auto_increment, crap char(2000));

insert into foo(crap) values ('');

-- each time you run the next line, the number of rows in foo doubles. insert into foo( crap ) select * from foo;

run it twenty more times, you have over a million rows to play with.

Yes, if he's looking for looks of relations to navigate, this is not the answer. But if by huge he means to test performance and his ability to optimize, this will do it. I did exactly this (and then updated with random values) to test an potential answer I had for another question. (And didn't answer it, because I couldn't come up with better performance than what that asker had.)

Had he asked for "complex", I'd have gien a differnt answer. To me,"huge" implies "lots of rows".

Because you don't need huge to play with tables and relations. Consider a table, by itself, with no nullable columns. How many different kinds of rows can there be? Only one, as all columns must have some value as none can be null.

Every nullable column multiples by two the number of different kinds of rows possible: a row where that column is null, an row where it isn't null.

Now consider the table, not in isolation. Consider a table that is a child table: for every child that has an FK to the parent, that, is a many-to-one, there can be 0, 1 or many children. So we multiply by three times the count we got in the previous step (no rows for zero, one for exactly one, two rows for many). For any grandparent to which the parent is a many, another three.

For many-to-many relations, we can have have no relation, a one-to-one, a one-to-many, many-to-one, or a many-to-many. So for each many-to-many we can reach in a graph from the table, we multiply the rows by nine -- or just like two one-to manys. If the many-to-many also has data, we multiply by the nullability number.

Tables that we can't reach in our graph -- those that we have no direct or indirect FK to, don't multiply the rows in our table.

By recursively multiplying the each table we can reach, we can come up with the number of rows needed to provide one of each "kind", and we need no more than those to test every possible relation in our schema. And we're nowhere near huge.

CSS scrollbar style cross browser

As of IE6 I believe you cannot customize the scroll bar using those properties. The Chris Coyier article linked to above goes into nice detail about the options for webkit proprietary css for customizing the scroll bar.

If you really want a cross browser solution that you can fully customize you're going to have to use some JS. Here is a link to a nice plugin for it called FaceScroll:

convert double to int

You can use a cast if you want the default truncate-towards-zero behaviour. Alternatively, you might want to use Math.Ceiling, Math.Round, Math.Floor etc - although you'll still need a cast afterwards.

Don't forget that the range of int is much smaller than the range of double. A cast from double to int won't throw an exception if the value is outside the range of int in an unchecked context, whereas a call to Convert.ToInt32(double) will. The result of the cast (in an unchecked context) is explicitly undefined if the value is outside the range.

How can I simulate an array variable in MySQL?

I know that this is a bit of a late response, but I recently had to solve a similar problem and thought that this may be useful to others.


Consider the table below called 'mytable':

Starting table

The problem was to keep only latest 3 records and delete any older records whose systemid=1 (there could be many other records in the table with other systemid values)

It would be good is you could do this simply using the statement

DELETE FROM mytable WHERE id IN (SELECT id FROM `mytable` WHERE systemid=1 ORDER BY id DESC LIMIT 3)

However this is not yet supported in MySQL and if you try this then you will get an error like

...doesn't yet support 'LIMIT & IN/ALL/SOME subquery'

So a workaround is needed whereby an array of values is passed to the IN selector using variable. However, as variables need to be single values, I would need to simulate an array. The trick is to create the array as a comma separated list of values (string) and assign this to the variable as follows

SET @myvar := (SELECT GROUP_CONCAT(id SEPARATOR ',') AS myval FROM (SELECT * FROM `mytable` WHERE systemid=1 ORDER BY id DESC LIMIT 3 ) A GROUP BY A.systemid);

The result stored in @myvar is


Next, the FIND_IN_SET selector is used to select from the simulated array

SELECT * FROM mytable WHERE FIND_IN_SET(id,@myvar);

The combined final result is as follows:

SET @myvar := (SELECT GROUP_CONCAT(id SEPARATOR ',') AS myval FROM (SELECT * FROM `mytable` WHERE systemid=1 ORDER BY id DESC LIMIT 3 ) A GROUP BY A.systemid);
DELETE FROM mytable WHERE FIND_IN_SET(id,@myvar);

I am aware that this is a very specific case. However it can be modified to suit just about any other case where a variable needs to store an array of values.

I hope that this helps.

Android-Studio upgraded from 0.1.9 to 0.2.0 causing gradle build errors now

if you get this error

FAILURE: Could not determine which tasks to execute.
* What went wrong:
Task 'assemble' not found in root project 'MyProject'.
* Try:
Run gradle tasks to get a list of available tasks.

You need to edit your Projects .iml file. not the one under src. the one that is like myappProject.iml' delete the whole component name = facetmanager

<module"GRADLE" type="JAVA_MODULE" version="4">
<component name="FacetManager">
...remove this element and everything inside such as <facet> elements...
<component name="NewModuleRootManager" inherit-compiler-output="true">
...keep this part...

Effective way to find any file's Encoding

The following codes are my Powershell codes to determinate if some cpp or h or ml files are encodeding with ISO-8859-1(Latin-1) or UTF-8 without BOM, if neither then suppose it to be GB18030. I am a Chinese working in France and MSVC saves as Latin-1 on french computer and saves as GB on Chinese computer so this helps me avoid encoding problem when do source file exchanges between my system and my colleagues.

The way is simple, if all characters are between x00-x7E, ASCII, UTF-8 and Latin-1 are all the same, but if I read a non ASCII file by UTF-8, we will find the special character ? show up, so try to read with Latin-1. In Latin-1, between \x7F and \xAF is empty, while GB uses full between x00-xFF so if I got any between the two, it's not Latin-1

The code is written in PowerShell, but uses .net so it's easy to be translated into C# or F#

$Utf8NoBomEncoding = New-Object System.Text.UTF8Encoding($False)
foreach($i in Get-ChildItem .\ -Recurse -include *.cpp,*.h, *.ml) {
    $openUTF = New-Object System.IO.StreamReader -ArgumentList ($i, [Text.Encoding]::UTF8)
    $contentUTF = $openUTF.ReadToEnd()
    [regex]$regex = '?'
    if ($c -ne 0) {
        $openLatin1 = New-Object System.IO.StreamReader -ArgumentList ($i, [Text.Encoding]::GetEncoding('ISO-8859-1'))
        $contentLatin1 = $openLatin1.ReadToEnd()
        [regex]$regex = '[\x7F-\xAF]'
        if ($c -eq 0) {
            [System.IO.File]::WriteAllLines($i, $contentLatin1, $Utf8NoBomEncoding)
        else {
            $openGB = New-Object System.IO.StreamReader -ArgumentList ($i, [Text.Encoding]::GetEncoding('GB18030'))
            $contentGB = $openGB.ReadToEnd()
            [System.IO.File]::WriteAllLines($i, $contentGB, $Utf8NoBomEncoding)
Write-Host -NoNewLine 'Press any key to continue...';
$null = $Host.UI.RawUI.ReadKey('NoEcho,IncludeKeyDown');

Get the time of a datetime using T-SQL?

You can try the following code to get time as HH:MM format:

 SELECT CONVERT(VARCHAR(5),getdate(),108)

Reading entire html file to String?

You should use a StringBuilder:

StringBuilder contentBuilder = new StringBuilder();
try {
    BufferedReader in = new BufferedReader(new FileReader("mypage.html"));
    String str;
    while ((str = in.readLine()) != null) {
} catch (IOException e) {
String content = contentBuilder.toString();

Trying to make bootstrap modal wider

Always have handy the un-minified CSS for bootstrap so you can see what styles they have on their components, then create a CSS file AFTER it, if you don't use LESS and over-write their mixins or whatever

This is the default modal css for 768px and up:

@media (min-width: 768px) {
  .modal-dialog {
    width: 600px;
    margin: 30px auto;

They have a class modal-lg for larger widths

@media (min-width: 992px) {
  .modal-lg {
    width: 900px;

If you need something twice the 600px size, and something fluid, do something like this in your CSS after the Bootstrap css and assign that class to the modal-dialog.

@media (min-width: 768px) {
  .modal-xl {
    width: 90%;


<div class="modal-dialog modal-xl">


Convert boolean result into number/integer

You could do this by simply extending the boolean prototype

Boolean.prototype.intval = function(){return ~~this}

It is not too easy to understand what is going on there so an alternate version would be

Boolean.prototype.intval = function(){return (this == true)?1:0}

having done which you can do stuff like


When I use booleans to store conditions I often convert them to bitfields in which case I end up using an extended version of the prototype function

Boolean.prototype.intval = function(places)
 places = ('undefined' == typeof(places))?0:places; 
 return (~~this) << places

with which you can do


which produces 4 as its output.

CSS text-transform capitalize on all caps

If the data is coming from a database, as in my case, you can lower it before sending it to a select list/drop down list. Shame you can't do it in CSS.

Abstraction VS Information Hiding VS Encapsulation

Abstraction allows you to treat a complex process as a simple process. For example, the standard "file" abstraction treats files as a contiguous array of bytes. The user/developer does not even have to think about issues of clusters and fragmentation. (Abstraction normally appears as classes or subroutines.)

Information hiding is about protecting your abstractions from malicious/incompetent users. By restricting control of some state (hard drive allocations, for example) to the original developer, huge amounts of error handling becomes redundant. If nobody else besides the file system driver can write to the hard drive, then the file system driver knows exactly what has been written to the hard drive and where. (The usual manifestation of this concept is private and protected keywords in OO languages.)

Looping from 1 to infinity in Python

Simplest and best:

i = 0
while not there_is_reason_to_break(i):
    # some code here
    i += 1

It may be tempting to choose the closest analogy to the C code possible in Python:

from itertools import count

for i in count():
    if thereIsAReasonToBreak(i):

But beware, modifying i will not affect the flow of the loop as it would in C. Therefore, using a while loop is actually a more appropriate choice for porting that C code to Python.

Counting the number of elements in array

Just use the length filter on the whole array. It works on more than just strings:

{{ notcount|length }}

Disable password authentication for SSH

In file /etc/ssh/sshd_config

# Change to no to disable tunnelled clear text passwords
#PasswordAuthentication no

Uncomment the second line, and, if needed, change yes to no.

Then run

service ssh restart

Difference between \b and \B in regex

\b is a zero-width word boundary. Specifically:

Matches at the position between a word character (anything matched by \w) and a non-word character (anything matched by [^\w] or \W) as well as at the start and/or end of the string if the first and/or last characters in the string are word characters.

Example: .\b matches c in abc

\B is a zero-width non-word boundary. Specifically:

Matches at the position between two word characters (i.e the position between \w\w) as well as at the position between two non-word characters (i.e. \W\W).

Example: \B.\B matches b in abc

See for more great regex info

How to throw RuntimeException ("cannot find symbol")

throw new RuntimeException(msg);

You need the new in there. It's creating an instance and throwing it, not calling a method.

Convert list into a pandas data frame

You need convert list to numpy array and then reshape:

df = pd.DataFrame(np.array(my_list).reshape(3,3), columns = list("abc"))
print (df)
   a  b  c
0  1  2  3
1  4  5  6
2  7  8  9

Angular 2 Sibling Component Communication

This is not what you exactly want but for sure will help you out

I'm surprised there's not more information out there about component communication <=> consider this tutorial by angualr2

For sibling components communication, I'd suggest to go with sharedService. There are also other options available though.

import {Component,bind} from 'angular2/core';
import {bootstrap} from 'angular2/platform/browser';
import {HTTP_PROVIDERS} from 'angular2/http';
import {NameService} from 'src/nameService';

import {TheContent} from 'src/content';
import {Navbar} from 'src/nav';

  selector: 'app',
  directives: [TheContent,Navbar],
  providers: [NameService],
  template: '<navbar></navbar><thecontent></thecontent>'

export class App {
  constructor() {
    console.log('App started');


Please refer to link at top for more code.

Edit: This is a very small demo. You have already mention that you have already tried with sharedService. So please consider this tutorial by angualr2 for more information.

Create a menu Bar in WPF?

        <MenuItem Header="File">
            <MenuItem Header="New">
               <MenuItem Header="File1"/>
               <MenuItem Header="File2"/>
               <MenuItem Header="File3"/>
            <MenuItem Header="Open"/>
            <MenuItem Header="Save"/>

How can I get the status code from an http error in Axios?

It's my code: Work for me

 var jsonData = request.body;
    var jsonParsed = JSON.parse(JSON.stringify(jsonData));

    // message_body = {
    //   "phone": "5511995001920",
    //   "body": "WhatsApp API on works good"
    // }, jsonParsed,validateStatus = true)
    .then((res) => {
      // console.log(`statusCode: ${res.statusCode}`)


        // var jsonData = res.body;
        // var jsonParsed = JSON.parse(JSON.stringify(jsonData));

    .catch((error) => {

JavaScript string and number conversion

You want to become familiar with parseInt() and toString().

And useful in your toolkit will be to look at a variable to find out what type it is—typeof:

<script type="text/javascript">
     * print out the value and the type of the variable passed in

    function printWithType(val) {
        document.write(' ');
        document.writeln(typeof val);

    var a = "1", b = "2", c = "3", result;

    // Step (1) Concatenate "1", "2", "3" into "123"
    // - concatenation operator is just "+", as long
    //   as all the items are strings, this works
    result = a + b + c;
    printWithType(result); //123 string

    // - If they were not strings you could do
    result = a.toString() + b.toString() + c.toString();
    printWithType(result); // 123 string

    // Step (2) Convert "123" into 123
    result = parseInt(result,10);
    printWithType(result); // 123 number

    // Step (3) Add 123 + 100 = 223
    result = result + 100;
    printWithType(result); // 223 number

    // Step (4) Convert 223 into "223"
    result = result.toString(); //
    printWithType(result); // 223 string

    // If you concatenate a number with a 
    // blank string, you get a string    
    result = result + "";
    printWithType(result); //223 string

How to lazy load images in ListView in Android

I have followed this Android Training and I think it does an excellent job at downloading images without blocking the main UI. It also handles caching and dealing with scrolling through many images: Loading Large Bitmaps Efficiently

Eclipse error: "The import XXX cannot be resolved"

This has solved my issue.

1) clean project Project -> clean...

2) Right click on project -> BuildPath -> Configure BuildPath -> Libraries tab -> Double click on JRE SYSTEM LIBRARY -> Then select alternate JRE

3) Click Save

4) Again go to your project in project explorer and right click to project -> BuildPath -> Configure BuildPath -> Libraries tab -> Double click on JRE SYSTEM LIBRARY -> This time select "Execution Environment"

5) Apply

Resizing an Image without losing any quality

I believe what you're looking to do is "Resize/Resample" your images. Here is a good site that gives instructions and provides a utility class(That I also happen to use):

MySQL set current date in a DATETIME field on insert

Using Now() is not a good idea. It only save the current time and date. It will not update the the current date and time, when you update your data. If you want to add the time once, The default value =Now() is best option. If you want to use timestamp. and want to update the this value, each time that row is updated. Then, trigger is best option to use.


These two toturial will help to implement the trigger.

How to draw a filled circle in Java?

public void paintComponent(Graphics g) {
   Graphics2D g2d = (Graphics2D)g;
   // Assume x, y, and diameter are instance variables.
   Ellipse2D.Double circle = new Ellipse2D.Double(x, y, diameter, diameter);

Here are some docs about paintComponent (link).

You should override that method in your JPanel and do something similar to the code snippet above.

In your ActionListener you should specify x, y, diameter and call repaint().

How can a Jenkins user authentication details be "passed" to a script which uses Jenkins API to create jobs?

In order to use API tokens, users will have to obtain their own tokens, each from https://<jenkins-server>/me/configure or https://<jenkins-server>/user/<user-name>/configure. It is up to you, as the author of the script, to determine how users supply the token to the script. For example, in a Bourne Shell script running interactively inside a Git repository, where .gitignore contains /.jenkins_api_token, you might do something like:

api_token_file="$(git rev-parse --show-cdup).jenkins_api_token"
api_token=$(cat "$api_token_file" || true)
if [ -z "$api_token" ]; then
    echo "Obtain your API token from $JENKINS_URL/user/$user/configure"
    echo "After entering here, it will be saved in $api_token_file; keep it safe!"
    read -p "Enter your Jenkins API token: " api_token
    echo $api_token > "$api_token_file"
curl -u $user:$api_token $JENKINS_URL/someCommand

Reading a .txt file using Scanner class in Java

No one seems to have addressed the fact that your not entering anything into an array at all. You are setting each int that is read to "i" and then outputting it.

for (int i =0 ; sc.HasNextLine();i++)
    array[i] = sc.NextInt();

Something to this effect will keep setting values of the array to the next integer read.

Than another for loop can display the numbers in the array.

for (int x=0;x< array.length ; x++)

Django Server Error: port is already in use

This is an expansion on Mounir's answer. I've added a bash script that covers this for you. Just run ./scripts/ instead of ./ runserver and it'll work exactly the same way.


pid=$(ps aux | grep "./ runserver" | grep -v grep | head -1 | xargs | cut -f2 -d" ")

if [[ -n "$pid" ]]; then
    kill $pid

fuser -k 8000/tcp
./ runserver

React: "this" is undefined inside a component function

You should notice that this depends on how function is invoked ie: when a function is called as a method of an object, its this is set to the object the method is called on.

this is accessible in JSX context as your component object, so you can call your desired method inline as this method.

If you just pass reference to function/method, it seems that react will invoke it as independent function.

onClick={this.onToggleLoop} // Here you just passing reference, React will invoke it as independent function and this will be undefined

onClick={()=>this.onToggleLoop()} // Here you invoking your desired function as method of this, and this in that function will be set to object from that function is called ie: your component object

fatal error: iostream.h no such file or directory

That header doesn't exist in standard C++. It was part of some pre-1990s compilers, but it is certainly not part of C++.

Use #include <iostream> instead. And all the library classes are in the std:: namespace, for ex­am­ple std::cout.

Also, throw away any book or notes that mention the thing you said.

Reading a json file in Android

Put that file in assets.

For project created in Android Studio project you need to create assets folder under the main folder.

Read that file as:

public String loadJSONFromAsset(Context context) {
        String json = null;
        try {
            InputStream is = context.getAssets().open("file_name.json");

            int size = is.available();

            byte[] buffer = new byte[size];



            json = new String(buffer, "UTF-8");

        } catch (IOException ex) {
            return null;
        return json;


and then you can simply read this string return by this function as

JSONObject obj = new JSONObject(json_return_by_the_function);

For further details regarding JSON see

Hope you will get what you want.

Retrieving parameters from a URL

import urlparse
url = ''
par = urlparse.parse_qs(urlparse.urlparse(url).query)

print par['q'][0], par['p'][0]

Convert Date format into DD/MMM/YYYY format in SQL Server

Simply get date and convert

Declare @Date as Date =Getdate()

Select Format(@Date,'dd/MM/yyyy') as [dd/MM/yyyy] // output: 22/10/2020
Select Format(@Date,'dd-MM-yyyy') as [dd-MM-yyyy] // output: 22-10-2020

//string date
Select Format(cast('25/jun/2013' as date),'dd/MM/yyyy') as StringtoDate // output: 25/06/2013

Source: SQL server date format and converting it (Various examples)

Set CSS property in Javascript?


var element = document.createElement('select'); = "100px";

Fill formula down till last row in column

It's a one liner actually. No need to use .Autofill

Range("M3:M" & LastRow).Formula = "=G3&"",""&L3"

Are arrays in PHP copied as value or as reference to new variables, and when passed to functions?

In PHP arrays are passed to functions by value by default, unless you explicitly pass them by reference, as the following snippet shows:

$foo = array(11, 22, 33);

function hello($fooarg) {
  $fooarg[0] = 99;

function world(&$fooarg) {
  $fooarg[0] = 66;

var_dump($foo); // (original array not modified) array passed-by-value

var_dump($foo); // (original array modified) array passed-by-reference

Here is the output:

array(3) {
array(3) {

Fetch: reject promise and catch the error if status is not OK?

Thanks for the help everyone, rejecting the promise in .catch() solved my issue:

export function fetchVehicle(id) {
    return dispatch => {
        return dispatch({
            type: 'FETCH_VEHICLE',
            payload: fetch(`${id}/`)
                .then(res => res.json())    
                .catch(error => {
                    return Promise.reject()

function status(res) {
    if (!res.ok) {
        throw new Error(res.statusText);
    return res;

What is the equivalent of Java's System.out.println() in Javascript?

You can always simply add an alert() prompt anywhere in a function. Especially useful for knowing if a function was called, if a function completed or where a function fails.

alert('start of function x');
alert('end of function y');
alert('about to call function a');
alert('returned from function b');

You get the idea.

Unable to add window -- token android.os.BinderProxy is not valid; is your activity running?

one simple workaround is to catch the exception :

try {
catch (WindowManager.BadTokenException e) {
        //use a log message

It's not elegant but sometimes easy when you have to manage async operations and you are not sure wether activity is up or not when you want to show the dialog.

Ajax post request in laravel 5 return error 500 (Internal Server Error)

In App\Http\Middleware\VerifyCsrfToken.php you could try updating the file to something like:

class VerifyCsrfToken extends BaseVerifier {

    private $openRoutes =
        ...excluded routes

    public function handle($request, Closure $next)
        foreach($this->openRoutes as $route)
            if ($request->is($route))
                return $next($request);

        return parent::handle($request, $next);

This allows you to explicitly bypass specific routes that you do not want verified without disabling csrf validation globally.

What is a postback?

Web developement generally involves html pages that hold forms (<form> tags). Forms post to URLs. You can set a given form to post to any url you want to. A postback is when a form posts back to it's own page/url.

The term has special significance for ASP.Net developers, because it is the primary mechanism that drives a lot of the behavior for a page -- specifically 'event handling'. ASP.Net pages have exactly one server form that nearly always posts back to itself, and these post backs trigger execution on the server of something called the Page Lifecycle.

How to debug a GLSL shader?

GLSL Sandbox has been pretty handy to me for shaders.

Not debugging per se (which has been answered as incapable) but handy to see the changes in output quickly.

T-SQL - function with default parameters

With user defined functions, you have to declare every parameter, even if they have a default value.

The following would execute successfully:

IF dbo.CheckIfSFExists( 23, default ) = 0
    SET @retValue = 'bla bla bla;

How to use mysql JOIN without ON condition?

See some example in

You can use 'USING' instead of 'ON' as in the query

SELECT * FROM table1 LEFT JOIN table2 USING (id);

html select option separator

This is an old thread, but since no one posted a similar response, I'll add this as it's my preferred way of separation.

I find using dashes and such to be somewhat of an eyesore since it could fall short of the width of the selection box. So, I prefer to use CSS to create my separators.. a simple background coloring.

  <option style="background-color: #cccccc;" disabled selected>Select An Option</option>_x000D_
  <option>First Option</option>_x000D_
  <option style="font-size: 1pt; background-color: #000000;" disabled>&nbsp;</option>_x000D_
  <option style="font-size: 1pt; background-color: #000000;" disabled>&nbsp;</option>_x000D_

Extracting Nupkg files using command line

With PowerShell 5.1 (PackageManagement module)

Install-Package -Name MyPackage -Source (Get-Location).Path -Destination C:\outputdirectory

When do you use Java's @Override annotation and why?

Use it every time you override a method for two benefits. Do it so that you can take advantage of the compiler checking to make sure you actually are overriding a method when you think you are. This way, if you make a common mistake of misspelling a method name or not correctly matching the parameters, you will be warned that you method does not actually override as you think it does. Secondly, it makes your code easier to understand because it is more obvious when methods are overwritten.

Additionally, in Java 1.6 you can use it to mark when a method implements an interface for the same benefits. I think it would be better to have a separate annotation (like @Implements), but it's better than nothing.

How to select a CRAN mirror in R

Add into ~/.Rprofile

local({r <- getOption("repos")
    r["CRAN"] <- "mirror_site"  #for example,
    options(BioC_mirror="bioc_mirror_site") #if using biocLite

How to find server name of SQL Server Management Studio

There are many ways mentioned above. But I use rather simple way (well not simple as SELECT @@SERVERNAME). When you start SQL server management studio you will prompt below GUI

enter image description here

In there Server name is your server name (There may have multiple servers according to you dev environment choose correct one). Hope this helps :)

How to stop a thread created by implementing runnable interface?

The simplest way is to interrupt() it, which will cause Thread.currentThread().isInterrupted() to return true, and may also throw an InterruptedException under certain circumstances where the Thread is waiting, for example Thread.sleep(), otherThread.join(), object.wait() etc.

Inside the run() method you would need catch that exception and/or regularly check the Thread.currentThread().isInterrupted() value and do something (for example, break out).

Note: Although Thread.interrupted() seems the same as isInterrupted(), it has a nasty side effect: Calling interrupted() clears the interrupted flag, whereas calling isInterrupted() does not.

Other non-interrupting methods involve the use of "stop" (volatile) flags that the running Thread monitors.

Filter multiple values on a string column in dplyr

 by_type_year_tag_filtered <- by_type_year_tag %>%
      dplyr:: filter(tag_name %in% c("dplyr", "ggplot2"))

AngularJS: How do I manually set input to $valid in controller?

I came across this post w/a similar issue. My fix was to add a hidden field to hold my invalid state for me.

<input type="hidden" ng-model="vm.application.isValid" required="" />

In my case I had a nullable bool which a person had to select one of two different buttons. if they answer yes, an entity is added to the collection and the state of the button changes. Until all of the questions get answered, (one of the buttons in each of the pairs has a click) the form is not valid.

vm.hasHighSchool = function (attended) { 
  vm.application.hasHighSchool = attended;
  applicationSvc.addSchool(attended, 1, vm.application);
<input type="hidden" ng-model="vm.application.hasHighSchool" required="" />
<div class="row">
  <div class="col-lg-3"><label>Did You Attend High School?</label><label class="required" ng-hide="vm.application.hasHighSchool != undefined">*</label></div>
  <div class="col-lg-2">
    <button value="Yes" title="Yes" ng-click="vm.hasHighSchool(true)" class="btn btn-default" ng-class="{'btn-success': vm.application.hasHighSchool == true}">Yes</button>
    <button value="No" title="No" ng-click="vm.hasHighSchool(false)" class="btn btn-default" ng-class="{'btn-success':  vm.application.hasHighSchool == false}">No</button>

"This operation requires IIS integrated pipeline mode."

I was having the same issue and I solved it doing the following:

  1. In Visual Studio, select "Project properties".

  2. Select the "Web" Tab.

  3. Select "Use Local IIS Web server".

  4. Check "Use IIS Express"

SQL Server add auto increment primary key to existing table

ALTER TABLE table_name ADD temp_col INT IDENTITY(1,1) 

Items in JSON object are out of order using "json.dumps"?

Both Python dict (before Python 3.7) and JSON object are unordered collections. You could pass sort_keys parameter, to sort the keys:

>>> import json
>>> json.dumps({'a': 1, 'b': 2})
'{"b": 2, "a": 1}'
>>> json.dumps({'a': 1, 'b': 2}, sort_keys=True)
'{"a": 1, "b": 2}'

If you need a particular order; you could use collections.OrderedDict:

>>> from collections import OrderedDict
>>> json.dumps(OrderedDict([("a", 1), ("b", 2)]))
'{"a": 1, "b": 2}'
>>> json.dumps(OrderedDict([("b", 2), ("a", 1)]))
'{"b": 2, "a": 1}'

Since Python 3.6, the keyword argument order is preserved and the above can be rewritten using a nicer syntax:

>>> json.dumps(OrderedDict(a=1, b=2))
'{"a": 1, "b": 2}'
>>> json.dumps(OrderedDict(b=2, a=1))
'{"b": 2, "a": 1}'

See PEP 468 – Preserving Keyword Argument Order.

If your input is given as JSON then to preserve the order (to get OrderedDict), you could pass object_pair_hook, as suggested by @Fred Yankowski:

>>> json.loads('{"a": 1, "b": 2}', object_pairs_hook=OrderedDict)
OrderedDict([('a', 1), ('b', 2)])
>>> json.loads('{"b": 2, "a": 1}', object_pairs_hook=OrderedDict)
OrderedDict([('b', 2), ('a', 1)])

Docker Error bind: address already in use

`$` sudo service redis-server stop

Does the trick.

SQL not a single-group group function

Maybe you find this simpler

select * from (
    select ssn, sum(time) from downloads
    group by ssn
    order by sum(time) desc
) where rownum <= 10 --top 10 downloaders


In a unix shell, how to get yesterday's date into a variable?

On Linux, you can use

date -d "-1 days" +"%a %d/%m/%Y"

What is ModelState.IsValid valid for in ASP.NET MVC in NerdDinner?

From the Errata: ModelState.AddRuleViolations(dinner.GetRuleViolations());

Should be:



no debugging symbols found when using gdb

You should also try -ggdb instead of -g if you're compiling for Android!

How to build jars from IntelliJ properly?

I recently had this problem and think these steps are easy to follow if any prior solution or link is missing detail.

How to create a .jar using IntelliJ IDEA 14.1.5:

  1. File > Save All.
  2. Run driver or class with main method.
  3. File > Project Structure.
  4. Select Tab "Artifacts".
  5. Click green plus button near top of window.
  6. Select JAR from Add drop down menu. Select "From modules with dependencies"
  7. Select main class.
  8. The radio button should be selecting "extract to the target JAR." Press OK.
  9. Check the box "Build on make"
  10. Press apply and OK.
  11. From the main menu, select the build dropdown.
  12. Select the option build artifacts.

What is the best way to remove a table row with jQuery?

Is the following acceptable:


How to call a MySQL stored procedure from within PHP code?

This is my solution with prepared statements and stored procedure is returning several rows not only one value.


require 'config.php';

$mIds = $_GET['ids'];

$stmt = $connection->prepare("CALL sp_takes_string_returns_table(?)");
$stmt->bind_param("s", $mIds);


$result = $stmt->get_result();
$response = $result->fetch_all(MYSQLI_ASSOC);
echo json_encode($response);


What is the @Html.DisplayFor syntax for?

I think the main benefit would be when you define your own Display Templates, or use Data annotations.

So for example if your title was a date, you could define

[DisplayFormat(DataFormatString = "{0:d}")]

and then on every page it would display the value in a consistent manner. Otherwise you may have to customise the display on multiple pages. So it does not help much for plain strings, but it does help for currencies, dates, emails, urls, etc.

For example instead of an email address being a plain string it could show up as a link:

<a href="mailto:@ViewData.Model">@ViewData.TemplateInfo.FormattedModelValue</a>

Android Stop Emulator from Command Line

To automate this, you can use any script or app that can send a string to a socket. I personally like nc (netcat) under cygwin. As I said before, I use it like this:

$ echo kill | nc -w 2 localhost 5554

(that means to send "kill" string to the port 5554 on localhost, and terminate netcat after 2 seconds.)

How to convert a String to Bytearray

If you are looking for a solution that works in node.js, you can use this:

var myBuffer = [];
var str = 'Stack Overflow';
var buffer = new Buffer(str, 'utf16le');
for (var i = 0; i < buffer.length; i++) {


Min width in window resizing

Well, you pretty much gave yourself the answer. In your CSS give the containing element a min-width. If you have to support IE6 you can use the min-width-trick:

#container {
    width: auto !important;

That will effectively give you 800px min-width in IE6 and any up-to-date browsers.

What's the UIScrollView contentInset property for?

It's used to add padding in UIScrollView

Without contentInset, a table view is like this:

enter image description here

Then set contentInset:

tableView.contentInset = UIEdgeInsets(top: 20, left: 0, bottom: 0, right: 0)

The effect is as below:

enter image description here

Seems to be better, right?

And I write a blog to study the contentInset, criticism is welcome.

Ideal way to cancel an executing AsyncTask

Just discovered that AlertDialogs's boolean cancel(...); I've been using everywhere actually does nothing. Great.

public class MyTask extends AsyncTask<Void, Void, Void> {

    private volatile boolean running = true;
    private final ProgressDialog progressDialog;

    public MyTask(Context ctx) {
        progressDialog = gimmeOne(ctx);

        progressDialog.setOnCancelListener(new OnCancelListener() {
            public void onCancel(DialogInterface dialog) {
                // actually could set running = false; right here, but I'll
                // stick to contract.


    protected void onPreExecute() {;

    protected void onCancelled() {
        running = false;

    protected Void doInBackground(Void... params) {

        while (running) {
            // does the hard work
        return null;

    // ...


Vue.js dynamic images not working

Your best bet is to just use a simple method to build the correct string for the image at the given index:

methods: {
  getPic(index) {
    return '../assets/' +[index] + '.png';

then do the following inside your v-for:

<div class="col-lg-2" v-for="(pic, index) in pics">
   <img :src="getPic(index)" v-bind:alt="pic">

Here's the JSFiddle (obviously the images don't show, so I've put the image src next to the image):

Windows 7: unable to register DLL - Error Code:0X80004005

Use following command should work on windows 7. don't forget to enclose the dll name with full path in double quotations.

C:\Windows\SysWOW64>regsvr32 "c:\" 

Change Select List Option background colour on hover

This way we can do this with minimal changes :)


    option:hover {
      background-color: yellow;

  <select onfocus='this.size=10;' onblur='this.size=0;' onchange='this.size=1; this.blur();'>
    <option value="volvo">Volvo</option>
    <option value="saab">Saab</option>
    <option value="opel">Opel</option>
    <option value="audi">Audi</option>
    <option value="volvo">Volvo</option>
    <option value="saab">Saab</option>
    <option value="opel">Opel</option>
    <option value="audi">Audi</option>
    <option value="volvo">Volvo</option>
    <option value="saab">Saab</option>
    <option value="opel">Opel</option>
    <option value="audi">Audi</option>
    <option value="volvo">Volvo</option>
    <option value="saab">Saab</option>
    <option value="opel">Opel</option>
    <option value="audi">Audi</option>



How can I set the opacity or transparency of a Panel in WinForms?

Don't forget to bring your Panel to the Front when dynamically creating it in the form constructor. Example of transparent panel overlay of tab control.

panel1 = new TransparentPanel();
panel1.BackColor = System.Drawing.Color.Transparent;
panel1.Location = new System.Drawing.Point(0, 0);
panel1.Name = "panel1";
panel1.Size = new System.Drawing.Size(717, 92);
panel1.TabIndex = 0;

// <== otherwise the other controls paint over top of the transparent panel

Apply function to each element of a list

Sometimes you need to apply a function to the members of a list in place. The following code worked for me:

>>> def func(a, i):
...     a[i] = a[i].lower()
>>> a = ['TEST', 'TEXT']
>>> list(map(lambda i:func(a, i), range(0, len(a))))
[None, None]
>>> print(a)
['test', 'text']

Please note, the output of map() is passed to the list constructor to ensure the list is converted in Python 3. The returned list filled with None values should be ignored, since our purpose was to convert list a in place

Disable same origin policy in Chrome

Following on Ola Karlsson answer, indeed the best way would be to open the unsafe Chrome in a different session. This way you don't need to worry about closing all of the currently opened tabs, and also can continue to surf the web securely with the original Chrome session.

These batch files should just work for you on Windows.

Put it in a Chrome_CORS.bat file for easy use

start "" "c:\Program Files (x86)\Google\Chrome\Application\chrome.exe" --user-data-dir="c:/_chrome_dev" --disable-web-security

This one is for Chrome Canary. Canary_CORS.bat

start "" "c:\Users\%USERNAME%\AppData\Local\Google\Chrome SxS\Application\chrome.exe" --user-data-dir="c:/_canary_dev" --disable-web-security

What is a handle in C++?

This appears in the context of the Handle-Body-Idiom, also called Pimpl idiom. It allows one to keep the ABI (binary interface) of a library the same, by keeping actual data into another class object, which is merely referenced by a pointer held in an "handle" object, consisting of functions that delegate to that class "Body".

It's also useful to enable constant time and exception safe swap of two objects. For this, merely the pointer pointing to the body object has to be swapped.

Android Studio - local path doesn't exist

Synchronize the project and all will done in version 1.1.0

Get last record of a table in Postgres

If under "last record" you mean the record which has the latest timestamp value, then try this:

my_query = client.query("
  FROM my_table

Creating multiline strings in JavaScript

to sum up, I have tried 2 approaches listed here in user javascript programming (Opera 11.01):

So I recommend the working approach for Opera user JS users. Unlike what the author was saying:

It doesn't work on firefox or opera; only on IE, chrome and safari.

It DOES work in Opera 11. At least in user JS scripts. Too bad I can't comment on individual answers or upvote the answer, I'd do it immediately. If possible, someone with higher privileges please do it for me.

Laravel 4 with Sentry 2 add user to a group on Registration

Somehow, where you are using Sentry, you're not using its Facade, but the class itself. When you call a class through a Facade you're not really using statics, it's just looks like you are.

Do you have this:

use Cartalyst\Sentry\Sentry; 

In your code?

Ok, but if this line is working for you:

$user = $this->sentry->register(array(     'username' => e($data['username']),     'email' => e($data['email']),      'password' => e($data['password'])     )); 

So you already have it instantiated and you can surely do:

$adminGroup = $this->sentry->findGroupById(5); 

Certificate has either expired or has been revoked

After all above step clean and Rebuild is also a factor.

Angular 4 checkbox change value

changed = (evt) => {    
this.isChecked =;

<input type="checkbox" [checked]="checkbox" (change)="changed($event)" id="no"/>

Mockito matcher and array of primitives

You can use Mockito.any() when arguments are arrays also. I used it like this:

verify(myMock, times(0)).setContents(any(), any());

Remove Item from ArrayList

String[] mString = new String[] {"B", "D", "F"};

for (int j = 0; j < mString.length-1; j++) {

find -exec with multiple commands

find . -type d -exec sh -c "echo -n {}; echo -n ' x '; echo {}" \;

Converting URL to String and back again

In Swift 4 and Swift 3, To convert String to URL:

URL(string: String)


URL.init(string: "yourURLString")

And to convert URL to String:


The one below converts the 'contents' of the url to string

String(contentsOf: URL)

How do include paths work in Visual Studio?

To use Windows SDK successfully you need not only make include files available to your projects but also library files and executables (tools). To set all these directories you should use WinSDK Configuration Tool.

How to display loading message when an iFrame is loading?

Here's a quick solution for most of the cases:


.iframe-loading { 
    background:url(/img/loading.gif) center center no-repeat; 

You can use an animated loading GIF if you want to,


<div class="iframe-loading">
    <iframe src="http://your_iframe_url_goes_here"  onload="$('.iframe-loading').css('background-image', 'none');"></iframe>

Using the onload event you can remove the loading image after the source page is loaded inside your iframe.

If you are not using jQuery, just put an id into the div and replace this part of code:

$('.iframe-loading').css('background-image', 'none');

by something like this:

document.getElementById("myDivName").style.backgroundImage = "none";

All the best!

How to initialize a vector with fixed length in R


X <- vector(mode="character", length=10)

This will give you empty strings which get printed as two adjacent double quotes, but be aware that there are no double-quote characters in the values themselves. That's just a side-effect of how print.default displays the values. They can be indexed by location. The number of characters will not be restricted, so if you were expecting to get 10 character element you will be disappointed.

>  X[5] <- "character element in 5th position"

>  X
 [1] ""                                  ""                                 
 [3] ""                                  ""                                 
 [5] "character element in 5th position" ""                                 
 [7] ""                                  ""                                 
 [9] ""                                  "" 
>  nchar(X)
 [1]  0  0  0  0 33  0  0  0  0  0

> length(X)
[1] 10

Bootstrap onClick button event

If, like me, you had dynamically created buttons on your page, the

$("#your-bs-button's-id").on("click", function(event) {
$(".your-bs-button's-class").on("click", function(event) {

methods won't work because they only work on current elements (not future elements). Instead you need to reference a parent item that existed at the initial loading of the web page.

$(document).on("click", "#your-bs-button's-id", function(event) {
                       or more generally
$("#pre-existing-element-id").on("click", ".your-bs-button's-class", function(event) {

There are many other references to this issue on stack overflow here and here.

configure Git to accept a particular self-signed server certificate for a particular https remote


  1. Get the self signed certificate
  2. Put it into some (e.g. ~/git-certs/cert.pem) file
  3. Set git to trust this certificate using http.sslCAInfo parameter

In more details:

Get self signed certificate of remote server

Assuming, the server URL is and you want to access it over port 443.

There are multiple options, how to get it.

Get certificate using openssl

$ openssl s_client -connect

Catch the output into a file cert.pem and delete all but part between (and including) -BEGIN CERTIFICATE- and -END CERTIFICATE-

Content of resulting file ~/git-certs/cert.pem may look like this:


Get certificate using your web browser

I use Redmine with Git repositories and I access the same URL for web UI and for git command line access. This way, I had to add exception for that domain into my web browser.

Using Firefox, I went to Options -> Advanced -> Certificates -> View Certificates -> Servers, found there the selfsigned host, selected it and using Export button I got exactly the same file, as created using openssl.

Note: I was a bit surprised, there is no name of the authority visibly mentioned. This is fine.

Having the trusted certificate in dedicated file

Previous steps shall result in having the certificate in some file. It does not matter, what file it is as long as it is visible to your git when accessing that domain. I used ~/git-certs/cert.pem

Note: If you need more trusted selfsigned certificates, put them into the same file:


This shall work (but I tested it only with single certificate).

Configure git to trust this certificate

$ git config --global http.sslCAInfo /home/javl/git-certs/cert.pem

You may also try to do that system wide, using --system instead of --global.

And test it: You shall now be able communicating with your server without resorting to:

$ git config --global http.sslVerify false #NO NEED TO USE THIS

If you already set your git to ignorance of ssl certificates, unset it:

$ git config --global --unset http.sslVerify

and you may also check, that you did it all correctly, without spelling errors:

$ git config --global --list

what should list all variables, you have set globally. (I mispelled http to htt).

How do I exclude Weekend days in a SQL Server query?

Assuming you're using SQL Server, use DATEPART with dw:

SELECT date_created
FROM your_table
WHERE DATEPART(dw, date_created) NOT IN (1, 7);

EDIT: I should point out that the actual numeric value returned by DATEPART(dw) is determined by the value set by using SET DATEFIRST:

Correlation heatmap

Another alternative is to use the heatmap function in seaborn to plot the covariance. This example uses the Auto data set from the ISLR package in R (the same as in the example you showed).

import pandas.rpy.common as com
import seaborn as sns
%matplotlib inline

# load the R package ISLR
infert = com.importr("ISLR")

# load the Auto dataset
auto_df = com.load_data('Auto')

# calculate the correlation matrix
corr = auto_df.corr()

# plot the heatmap

enter image description here

If you wanted to be even more fancy, you can use Pandas Style, for example:

cmap = cmap=sns.diverging_palette(5, 250, as_cmap=True)

def magnify():
    return [dict(selector="th",
                 props=[("font-size", "7pt")]),
                 props=[('padding', "0em 0em")]),
                 props=[("font-size", "12pt")]),
            dict(selector="tr:hover td:hover",
                 props=[('max-width', '200px'),
                        ('font-size', '12pt')])
], axis=1)\
    .set_properties(**{'max-width': '80px', 'font-size': '10pt'})\
    .set_caption("Hover to magify")\

enter image description here

Facebook user url by id

UPDATE 2: This information is no more given by facebook. There is an official announcement for the behavior change ( but none for its alternative.

Yes, Just use this link and append your ID to the id parameter:<UID>

So for example:

Will redirect you automatically to Which is Mark Zuckerberg's profile.

If you want to do this for all your ids, then you can do it using a loop.

If you'd like, I can provide you with a snippet.

UPDATE: Alternatively, You can also do this:<UID>

So that would be: which would automatically redirect to Zuck!

Convert from DateTime to INT

Or, once it's already in SSIS, you could create a derived column (as part of some data flow task) with:


But you'd have to test to doublecheck.

Getting the difference between two sets

If you use Guava (former Google Collections) library there is a solution:

SetView<Number> difference =, test1);

The returned SetView is a Set, it is a live representation you can either make immutable or copy to another set. test1 and test2 are left intact.

Getting value from appsettings.json in .net core

    public static void GetSection()
        Configuration = new ConfigurationBuilder()

        string BConfig = Configuration.GetSection("ConnectionStrings")["BConnection"];


How to remove the left part of a string?

The simplest way I can think of is with slicing:

def find_path(i_file): 
    lines = open(i_file).readlines() 
    for line in lines: 
        if line.startswith("Path=") : 
            return line[5:]

A quick note on slice notation, it uses two indices instead of the usual one. The first index indicates the first element of the sequence you want to include in the slice and the last index is the index immediately after the last element you wish to include in the slice.


The slice consists of all the elements between first_index and last_index, including first_index and not last_index. If the first index is omitted, it defaults to the start of the sequence. If the last index is omitted, it includes all elements up to the last element in the sequence. Negative indices are also allowed. Use Google to learn more about the topic.

How to delete all files and folders in a folder by cmd call

One easy one-line option is to create an empty directory somewhere on your file system, and then use ROBOCOPY ( with the /MIR switch to remove all files and subfolders. By default, robocopy does not copy security, so the ACLs in your root folder should remain intact.

Also probably want to set a value for the retry switch, /r, because the default number of retries is 1 million.

robocopy "C:\DoNotDelete_UsedByScripts\EmptyFolder" "c:\temp\MyDirectoryToEmpty" /MIR /r:3

How to print to console in pytest?

Using -s option will print output of all functions, which may be too much.

If you need particular output, the doc page you mentioned offers few suggestions:

  1. Insert assert False, "dumb assert to make PyTest print my stuff" at the end of your function, and you will see your output due to failed test.

  2. You have special object passed to you by PyTest, and you can write the output into a file to inspect it later, like

    def test_good1(capsys):
        for i in range(5):
            print i
        out, err = capsys.readouterr()
        open("err.txt", "w").write(err)
        open("out.txt", "w").write(out)

    You can open the out and err files in a separate tab and let editor automatically refresh it for you, or do a simple py.test; cat out.txt shell command to run your test.

That is rather hackish way to do stuff, but may be it is the stuff you need: after all, TDD means you mess with stuff and leave it clean and silent when it's ready :-).

NuGet: 'X' already has a dependency defined for 'Y'

I was getting the issue 'Newtonsoft.Json' already has a dependency defined for 'Microsoft.CSharp' on the TeamCity build server. I changed the "Update Mode" of the Nuget Installer build step from solution file to packages.config and NuGet.exe to the latest version (I had 3.5.0) and it worked !!

Python/BeautifulSoup - how to remove all tags from an element?

You can use the decompose method in bs4:

soup = bs4.BeautifulSoup('<body><a href="">I linked to <i></i></a></body>')

for a in soup.find('a').children:
    if isinstance(a,bs4.element.Tag):

print soup

Out: <html><body><a href="">I linked to </a></body></html>

Getting checkbox values on submit

//retrive check box and gender value
            Male<input type="radio" name="gender" value="1" <?php echo ($gender== '1') ?  "checked" : "" ;  ?>/>
            Female<input type="radio" name="gender" value="0" <?php echo ($gender== '0') ?  "checked" : "" ;  ?>/>

        <pre><?php //print_r($row);

            $hby = @explode(",",$row['chkhobby']);
        read<input id="check_1" type="checkbox" name="chkhobby[]" value="read" <?php if(in_array("read",$hby)){?> checked="checked"<?php }?>>
        write<input id="check_2" type="checkbox" name="chkhobby[]" value="write" <?php if(in_array("write",$hby)){?> checked="checked"<?php }?>>
        play<input id="check_4" type="checkbox" name="chkhobby[]" value="play" <?php if(in_array("play",$hby)){?> checked="checked"<?php }?>>

$chkhobby = implode(',', $_POST['chkhobby']);

Spring Boot Program cannot find main class

This happened to me after i updated the pom (Added some dependencies).

The following step helped me to avoid this error

right click on the project > maven > update project

How can I list all foreign keys referencing a given table in SQL Server?

I have been using this on 2008 and up. It's similar to some other solutions listed but, the field names are proper cased to handle case specific (LatBin) collations. Additionally, you can feed it a single table name and retrieve just the info for that table.

USE ???



DECLARE @tblName VARCHAR(255) 


    SET @tblName = NULL-->NULL will return all PK/FK constraints for every table in the database


       -- Force the column to be non-nullable (see SQL BU 325751) 
       KEY_SEQ             = isnull(convert(smallint,K.constraint_column_id),0), 
                                        WHEN 1 THEN 0 
                                        ELSE 1 
                                        WHEN 1 THEN 0 
                                        ELSE 1 
FROM   sys.all_objects O1, 
       sys.all_objects O2, 
       sys.all_columns C1, 
       sys.all_columns C2, 
       sys.foreign_keys F 
       INNER JOIN sys.foreign_key_columns K 
         ON (K.constraint_object_id = F.object_id) 
       INNER JOIN sys.indexes I 
         ON (F.referenced_object_id = I.object_id 
             AND F.key_index_id = I.index_id) 
WHERE  O1.object_id = F.referenced_object_id 
       AND O2.object_id = F.parent_object_id 
       AND C1.object_id = F.referenced_object_id 
       AND C2.object_id = F.parent_object_id 
       AND C1.column_id = K.referenced_column_id
       AND C2.column_id = K.parent_column_id
       AND ( = @tblName 
            OR = @tblName
            OR @tblName IS null)

How to return only the Date from a SQL Server DateTime datatype

If you need the result as a varchar, you should go through

SELECT CONVERT(VARCHAR(10), GETDATE(), 111) --2014/03/26

which is already mentioned above.

If you need result in date and time format, you should use any of the queries below


    2014-03-26 00:00:00.000


    2014-03-26 00:00:00.000

    SET @OnlyDate = DATEDIFF(DD, 0, GETDATE())
    SELECT @OnlyDate AS OnlyDate

    2014-03-26 00:00:00.000

shuffling/permutating a DataFrame in pandas

Use numpy's random.permuation function:

In [1]: df = pd.DataFrame({'A':range(10), 'B':range(10)})

In [2]: df
   A  B
0  0  0
1  1  1
2  2  2
3  3  3
4  4  4
5  5  5
6  6  6
7  7  7
8  8  8
9  9  9

In [3]: df.reindex(np.random.permutation(df.index))
   A  B
0  0  0
5  5  5
6  6  6
3  3  3
8  8  8
7  7  7
9  9  9
1  1  1
2  2  2
4  4  4

What is the difference between .py and .pyc files?

.pyc contain the compiled bytecode of Python source files. The Python interpreter loads .pyc files before .py files, so if they're present, it can save some time by not having to re-compile the Python source code. You can get rid of them if you want, but they don't cause problems, they're not big, and they may save some time when running programs.

Facebook OAuth "The domain of this URL isn't included in the app's domain"

If your game has no server/site (e.g. if you develop for Gameroom like me) - add "" (put your app ID instead of "xxxxxxxxxxxx") to "Valid OAuth Redirect URIs".

Sort objects in an array alphabetically on one property of the array

After try a little bit on this, and trying to make less loops as possible, I ended up with this solution:

Demo on codepen

const items = [
        name: 'One'
        name: 'Maria is here'
        name: 'Another'
        name: 'Z with a z'
        name: '1 number'
        name: 'Two not a number'
        name: 'Third'
        name: 'Giant'

    const sorted = items.sort((a, b) => {
      return a[name] > b[name];

    let sortedAlphabetically = {};

    for(var item in sorted) {
      const firstLetter = sorted[item].name[0];
      if(sortedAlphabetically[firstLetter]) {
      } else {
        sortedAlphabetically[firstLetter] = [sorted[item]]; 

    console.log('sorted', sortedAlphabetically);

In Angular, What is 'pathmatch: full' and what effect does it have?

pathMatch = 'full' results in a route hit when the remaining, unmatched segments of the URL match is the prefix path

pathMatch = 'prefix' tells the router to match the redirect route when the remaining URL begins with the redirect route's prefix path.


pathMatch: 'full' means, that the whole URL path needs to match and is consumed by the route matching algorithm.

pathMatch: 'prefix' means, the first route where the path matches the start of the URL is chosen, but then the route matching algorithm is continuing searching for matching child routes where the rest of the URL matches.

Converting Varchar Value to Integer/Decimal Value in SQL Server

You can use it without casting such as:

select sum(`stuff`) as mySum from test;

Or cast it to decimal:

select sum(cast(`stuff` as decimal(4,2))) as mySum from test;



For SQL Server, you can use:

select sum(cast(stuff as decimal(5,2))) as mySum from test;


Maven Jacoco Configuration - Exclude classes/packages from report not working

Another solution:

                    <rule implementation="org.jacoco.maven.RuleConfiguration">
                            <limit implementation="">

Please note that, we are using "<element>PACKAGE</element>" in the configuration which then helps us to exclude at package level.

PowerShell script to check the status of a URL

For people that have PowerShell 3 or later (i.e. Windows Server 2012+ or Windows Server 2008 R2 with the Windows Management Framework 4.0 update), you can do this one-liner instead of invoking System.Net.WebRequest:

$statusCode = wget | % {$_.StatusCode}

Best programming based games


It's usually easy for new programmers to pick up on languages like C++ when you have a strong understanding of Java basics. Colobot allows you to program automated craft using a language almost identical to Java and to move, sense, and manipulate their environment in order to accomplish missions on a dangerous planet.

W3WP.EXE using 100% CPU - where to start?

If your CPU is spiking to 100% and staying there, it's quite likely that you either have a deadlock scenario or an infinite loop. A profiler seems like a good choice for finding an infinite loop. Deadlocks are much more difficult to track down, however.

Gson: Is there an easier way to serialize a map


The default Gson implementation of Map serialization uses toString() on the key:

Gson gson = new GsonBuilder()
Map<Point, String> original = new HashMap<>();
original.put(new Point(1, 2), "a");
original.put(new Point(3, 4), "b");

Will give:

  "java.awt.Point[x\u003d1,y\u003d2]": "a",
  "java.awt.Point[x\u003d3,y\u003d4]": "b"

Using enableComplexMapKeySerialization

If you want the Map Key to be serialized according to default Gson rules you can use enableComplexMapKeySerialization. This will return an array of arrays of key-value pairs:

Gson gson = new GsonBuilder().enableComplexMapKeySerialization()
Map<Point, String> original = new HashMap<>();
original.put(new Point(1, 2), "a");
original.put(new Point(3, 4), "b");

Will return:

      "x": 1,
      "y": 2
      "x": 3,
      "y": 4

More details can be found here.

NodeJS accessing file with relative path

You can use the path module to join the path of the directory in which helper1.js lives to the relative path of foobar.json. This will give you the absolute path to foobar.json.

var fs = require('fs');
var path = require('path');

var jsonPath = path.join(__dirname, '..', 'config', 'dev', 'foobar.json');
var jsonString = fs.readFileSync(jsonPath, 'utf8');

This should work on Linux, OSX, and Windows assuming a UTF8 encoding.

Center a column using Twitter Bootstrap 3

Use mx-auto in your div class using Bootstrap 4.

<div class="container">
  <div class="row">
    <div class="mx-auto">
      You content here

Getting the closest string match

A very, very good resource for these kinds of algorithms is Simmetrics:

Unfortunately the awesome website containing a lot of the documentation is gone :( In case it comes back up again, its previous address was this:

Voila (courtesy of "Wayback Machine"):

You can study the code source, there are dozens of algorithms for these kinds of comparisons, each with a different trade-off. The implementations are in Java.

jquery, find next element by class

In this case you need to go up to the <tr> then use .next(), like this:


Or if there may be rows in-between without the .class inside, you can use .nextAll(), like this:


Java HTML Parsing

Several years ago I used JTidy for the same purpose:

"JTidy is a Java port of HTML Tidy, a HTML syntax checker and pretty printer. Like its non-Java cousin, JTidy can be used as a tool for cleaning up malformed and faulty HTML. In addition, JTidy provides a DOM interface to the document that is being processed, which effectively makes you able to use JTidy as a DOM parser for real-world HTML.

JTidy was written by Andy Quick, who later stepped down from the maintainer position. Now JTidy is maintained by a group of volunteers.

More information on JTidy can be found on the JTidy SourceForge project page ."

VarBinary vs Image SQL Server Data Type to Store Binary Data?

Since image is deprecated, you should use varbinary.

per Microsoft (thanks for the link @Christopher)

ntext , text, and image data types will be removed in a future version of Microsoft SQL Server. Avoid using these data types in new development work, and plan to modify applications that currently use them. Use nvarchar(max), varchar(max), and varbinary(max) instead.

Fixed and variable-length data types for storing large non-Unicode and Unicode character and binary data. Unicode data uses the UNICODE UCS-2 character set.

Delete topic in Kafka

If you have issues deleting the topics, try to delete the topic using:

$KAFKA_HOME/bin/ --delete --zookeeper localhost:2181 --topic your_topic_name

command. Then in order to verify the deletion process, go to the kafka logs directory which normally is placed under /tmp/kafka-logs/, then delete the your_topic_name file via rm -rf your_topic_name command.

Remember to monitor the whole process via a kafka management tool like Kafka Tool.

The mentioned process above will remove the topics without kafka server restart.

How to compare two tables column by column in oracle

Try to use 3rd party tool, such as SQL Data Examiner which compares Oracle databases and shows you differences.

How to read files from resources folder in Scala?

Resources in Scala work exactly as they do in Java. It is best to follow the Java best practices and put all resources in src/main/resources and src/test/resources.

Example folder structure:

+-- build.sbt
+-- src
¦   +-- main
¦       +-- resources
¦       ¦   +-- readme.txt

Scala 2.12.x && 2.13.x reading a resource

To read resources the object Source provides the method fromResource.

val readmeText : Iterator[String] = Source.fromResource("readme.txt").getLines

reading resources prior 2.12 (still my favourite due to jar compatibility)

To read resources you can use getClass.getResource and getClass.getResourceAsStream .

val stream: InputStream = getClass.getResourceAsStream("/readme.txt")
val lines: Iterator[String] = stream ).getLines

nicer error feedback (2.12.x && 2.13.x)

To avoid undebuggable Java NPEs, consider:

import scala.util.Try

object Example {

  def readResourceWithNiceError(resourcePath: String): Try[Iterator[String]] = 
      .recover(throw new FileNotFoundException(resourcePath))

good to know

Keep in mind that getResourceAsStream also works fine when the resources are part of a jar, getResource, which returns a URL which is often used to create a file can lead to problems there.

in Production

In production code I suggest to make sure that the source is closed again.

Python: import module from another directory at the same level in project hierarchy

In the "root" you can also do a

import sys
sys.path.insert(1, '.')

which should make both modules importable.

How to replace all occurrences of a string in Javascript?

If the string contain similar pattern like abccc, you can use this:

str.replace(/abc(\s|$)/g, "")