Can I build x64 app on a 32 bit machine?

Question

How do I develop a 64bit app on a 32 bit PC?

I'm using VS 2008 on WinXP 32 bit. I set the visual studio linker to /machine:x64 and created x64 configurations. All will compile and link OK, but when I run the dependency walker on the exe I see the 64 bit mscvr90.dll, etc. pointing to all the Win32 dlls, Kernel32.dll, Advapi32, Comdlg32, Gdi32, etc.

When I copy the exe over to run on a Win64 system it is rejected "...application configuration is incorrect". How do I tell visual studio to stay away from the 32 bit realm?

Answer 1

Sure you can. More info:

• Microsoft Visual C++ 2008 Redistributable Package (x64) - make sure you have it
• Installing Visual Studio 64-bit Components at MSDN
• 64-bit Applications at MSDN
• Compiling 64-bit applications in Visual Studio 2005

Answer 2

Yes, it's called cross-compiling.

http://blogs.msdn.com/windowssdk/archive/2007/09/08/updated-windows-sdk-visual-c-cross-compilers.aspx

Answer 3

Your problem with "rejected" executable is probably that you lack a correct manifest file, and/or that the vc2008 runtimes haven't been (properly) installed on the system. You probably need this runtime package (VS2008 native redistributables, x64 version) on the target system, if not using a .msi based install.

Even in 64bit windows, the DLLs still have their 32bit names (which imho was a bad choice, since it obviously confuses people). 32bit applications will by default have %systemroot%\system32 redirected to %systemroot%\syswow64 (where the 32bit DLLs reside), whereas 64bit applications won't get redirected. Registry access by 32bit applications also has some redirection involved. Both can be disabled per-thread with Wow64DisableWow64FsRedirection(), but obviously doesn't let 32bit applications load 64bit DLLs.

Answer 4

Since you are using VS2008, you will either have to copy the redist package along with your application on to the test machine or compile the runtime as a static library within your code.