What does the Visual Studio Any CPU target mean

Question

I have some confusion related to the  NET platform build options in Visual Studio 2008   What is the  Any CPU  compilation target  and what sort of files does it generate  I examined the output executable of this  Any CPU  build and found that they are the x86 executables  who would not see that coming    So  is there any difference between targeting executable to x86 vs   Any CPU    Another thing that I noticed  is that managed C   projects do not have this platform as an option  Why is that  Does that mean that my suspicion about  Any CPU  executables being plain 32-bit ones is right

User · Answer

I think most of the important stuff has been said, but I just thought I'd add one thing: If you compile as Any CPU and run on an x64 platform, then you won't be able to load 32-bit DLL files, because your application wasn't started in WoW64, but those DLL files need to run there.

If you compile as x86, then the x64 system will run your application in WoW64, and you'll be able to load 32-bit DLL files.

So I think you should choose "Any CPU" if your dependencies can run in either environment, but choose x86 if you have 32-bit dependencies. This article from Microsoft explains this a bit:

/CLRIMAGETYPE (Specify Type of CLR Image)

Incidentally, this other Microsoft documentation agrees that x86 is usually a more portable choice:

Choosing x86 is generally the safest configuration for an app package since it will run on nearly every device. On some devices, an app package with the x86 configuration won't run, such as the Xbox or some IoT Core devices. However, for a PC, an x86 package is the safest choice and has the largest reach for device deployment. A substantial portion of Windows 10 devices continue to run the x86 version of Windows.

User · Answer

Any CPU  means that when the program is started  the  NET Framework will figure out  based on the OS bitness  whether to run your program in 32 bits or 64 bits   There is a difference between x86 and Any CPU  on a x64 system  your executable compiled for X86 will run as a 32-bit executable   As far as your suspicions go  just go to the Visual nbsp Studio nbsp 2008 command line and run the following   dumpbin YourProgram exe  headers   It will tell you the bitness of your program  plus a whole lot more

User · Answer

Credit to the book  CLR via C    see this

User · Answer

I recommend reading this post   When using AnyCPU  the semantics are the following         If the process runs on a 32-bit Windows system  it runs as a 32-bit process  CIL is compiled to x86 machine code    If the process runs on a 64-bit Windows system  it runs as a 32-bit process  CIL is compiled to x86 machine code    If the process runs on an ARM Windows system  it runs as a 32-bit process  CIL is compiled to ARM machine code

User · Answer

Any CPU means that it will work on any platform   This is because managed code is similar to Java   Think of it as being compiled to a byte code that is interpreted by the  NET Framework at run-time   C   does not have this option because it is compiled to machine code that is platform specific

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Here s a quick overview that explains the different build targets   From my own experience  if you re looking to build a project that will run on both x86 and x64 platforms  and you don t have any specific x64 optimizations  I d change the build to specifically say  x86     The reason for this is sometimes you can get some DLL files that collide or some code that winds up crashing WoW in the x64 environment  By specifically specifying x86  the x64 OS will treat the application as a pure x86 application and make sure everything runs smoothly

User · Answer

An AnyCPU assembly will JIT to 64-bit code when loaded into a 64-bit process and 32 bit when loaded into a 32-bit process   By limiting the CPU you would be saying  There is something being used by the assembly  something likely  unmanaged  that requires 32 bits or 64 bits

User · Answer

Check out the article Visual Studio  NET Platform Target Explained      The default setting   Any CPU   means that the assembly will run   natively on the CPU it is currently running on   Meaning  it will run   as 64-bit on a 64-bit machine and 32-bit on a 32-bit machine   If the   assembly is called from a 64-bit application  it will perform as a   64-bit assembly and so on    The above link has been reported to be broken  so here is another article with a similar explanation  What AnyCPU Really Means As Of  NET 4 5 and Visual Studio 11

[.net] What does the Visual Studio "Any CPU" target mean?

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