LNK2019 unresolved external symbol main referenced in function tmainCRTStartup

Question

I have the following error LNK2019  unresolved external symbol  main referenced in function    tmainCRTStartup    There are a lot of threads relating to this error but none of those solutions worked for me  And  none explained why this error is here   I tried    wWinMainCRTStartup as entry point in the linker properties http   social msdn microsoft com Forums en vclanguage thread 14e85604-6929-4707-a22e-8cdf596926a6 set the linker to  Windows   same thread as above  Right click on solution name- Add- Existing Item- file with main  same thread as above  include  error LNK2019  unresolved external symbol  main referenced in function    tmainCRTStartup try Project   properties  C C    Code generation  Buffer security check   No http   social msdn microsoft com Forums hi-IN vclanguage thread e2ea62c3-beb3-47a4-8963-60b799e3375a Options  C C    Code generation  Runtime library  MTd  C C    Code generation  Basic Runtime Checks default  C C    Code generation  Buffer security check No  Linker  Advanced  Entry Point main http   social msdn microsoft com Forums hi-IN vclanguage thread e2ea62c3-beb3-47a4-8963-60b799e3375a commented out headers in main cpp except  using namespace std  and  include  - results in cascading and snowballing error from functions that referencing those headers I deleted everything in main cpp except test code and excluded all source files except main cpp  as expected it worked  so a small step in the right direction  The problem must be with one of the header files  create new project with Win32 Windows application template http   social msdn microsoft com Forums ar-SA vcgeneral thread 105a366f-c38d-4c1c-9278-eca64589e7ca and http   social msdn microsoft com Forums zh Vsexpressvc thread 341780c2-162e-4b36-9402-283c0cf7c0ac   have not tried and suspect that these also will not work    use int main    not sure what they mean  file name or main function name  http   social msdn microsoft com Forums zh Vsexpressvc thread 341780c2-162e-4b36-9402-283c0cf7c0ac using cmake to build on windows 7 x64 http   hdf-forum 184993 n3 nabble com error-LNK2019-unresolved-external-symbol-main-referenced-in-function-tmainCRTStartup-td3138042 html   why am I getting this error and what is the solution

User · Answer

I find that  when i choose option of   Project- Properties- Linker- System- SubSystem- Console  subsystem console   and then make sure include   the function   int  tmain int argc  TCHAR  argv    return 0  all of the compiling  linking and  running   will be ok

User · Answer

Because it hasn t been mentioned yet  this was the solution for me   I had this error with a DLL after creating a new configuration for my project  I had to go to Project Properties - gt  Configuration Properties - gt  General and change the Configuration Type to Dynamic Library   dll    So if you re still having trouble after trying everything else  it s worth checking to see if the configuration type is what you expect for your project  If it s not set correctly  the compiler will be looking for the wrong main symbol  In my case  it was looking for WinMain instead of DllMain

User · Answer

this main works in both linux and windows - found it through trial and error and help from others so can t explain why it works  it just does int main int argc  char   argv   no tchar h necessary  and here is the same answer in Wikipedia Main function

User · Answer

I had this error when accidentally putting the wmain inside a namespace  wmain should not be in any namespace  Moreover  I had a main function in one of the libs I was using  and VS took the main from there  what made it even stranger

User · Answer

I had the problem before  but it was solved  The main problem was that I mistakenly spell the int main   function  Instead of writing int main   I wrote int mian      Cheers

User · Answer

What is your project type  If it s a  Win32 project   your entry point should be  w WinMain  If it s a  Win32 Console Project   then it should be  w main  The name  tmain is  defined to be either main or wmain depending on whether UNICODE is defined or not   If it s a DLL  then DllMain   The project type can be seen under project properties  Linker  System  Subsystem  It would say either  Console  or  Windows    Note that the entry point name varies depending on whether UNICODE is defined or not  In VS2008  it s defined by default   The proper prototype for main is either  int  tmain int argc   TCHAR  argv      or   int  tmain     Make sure it s one of those   EDIT   If you re getting an error on  TCHAR  place an   include  lt tchar h gt    If you think the issue is with one of the headers  go to the properties of the file with main    and under Preprocessor  enable generating of the preprocessed file  Then compile  You ll get a file with the same name a  i extension  Open it  and see if anything unsavory happened to the main   function  There can be rogue  defines in theory     EDIT2   With UNICODE defined  which is the default   the linker expects the entry point to be wmain    not main     tmain has the advantage of being UNICODE-agnostic - it translates to either main or wmain   Some time ago  there was a reason to maintain both an ANSI build and a Unicode build  Unicode support was sorely incomplete in Windows 95 98 Me  The primary APIs were ANSI  and Unicode versions existed here and there  but not pervasively  Also  the VS debugger had trouble displaying Unicode strings  In the NT kernel OSes  that s Windows 2000 XP Vista 7 8 10   Unicode support is primary  and ANSI functions are added on top  So ever since VS2005  the default upon project creation is Unicode  That means - wmain  They could not keep the same entry point name because the parameter types are different   TCHAR is  defined to be either char or wchar t  So  tmain is either main int argc  char   argv  or wmain int argc  wchar t   argv    The reason you were getting an error at  tmain at some point was probably because you did not change the type of argv to  TCHAR     If you re not planning to ever support ANSI  probably not   you can reformulate your entry point as  int wmain int argc  wchar t  argv      and remove the tchar h include line

User · Answer

I had this problem minutes ago   It went away when I added  extern  C   to the main   definition      Oddly  another simple program I wrote yesterday is almost identical  does not have the extern  C   yet compiled without this linker error      This makes me think the problem is some subtle setting to be found deep in some configuration dialog  and that  extern  C   doesn t really solve the underlying problem  but superficially makes things work

User · Answer

In my case  it s because I accidentally removed  not deleted  the stdafx h and targetver h files in the Header Files section   Add these files back to Header Files and the problem is solved   I had these    pragma comment  linker    entry   mainCRTStartup         set the entry point to be main     I just need to comment that  by prepending     and it s good

User · Answer

Set the system to console  following the previous suggestions  Only  also had to change the character set to Unicode  see the snapshot of Visual Studio 2015 above

User · Answer

If you have a  Win32 project    defined a WinMain and your SubSystem linker setting is set to WINDOWS you can still get this linker error in case somebody set the  Additional Options  in the linker settings to   SUBSYSTEM CONSOLE   looks like this additional setting is preferred over the actual SubSystem setting

User · Answer

I got this error while I was trying to turn off precompiled headers in a Console Application Project and removing the header file stdafx h  To fix this go to your project properties -  Linker -  SubSystem  and change the value to Not Set  In your main class  use the standard C   main function protoype that others have already mentioned    int main int argc  char   argv

User · Answer

I had this happen in Visual Studio 2015 too for an interesting reason  Just adding it here in case it happens to someone else   I already had number of files in project and I was adding another one that would have main function in it  however when I initially added the file I made a typo in the extension   coo instead of  cpp   I corrected that but when I was done I got this error  It turned out that Visual Studio was being smart and when file was added it decided that it is not a source file due to the initial extension   Right-clicking on file in solution explorer and selecting Properties -  General -  ItemType and setting it to  C C   compiler  fixed the issue

[c++] LNK2019: unresolved external symbol _main referenced in function ___tmainCRTStartup

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