Visual Studio 2012 undocumented warning C4447

Question

dllmain.cpp(16): warning C4447: 'main' signature found without threading mode
l. Consider using 'int main(Platform::Array<Platform::String^>^ args)'.

Above is a warning I got from building a Windows Store App DLL project. I didn't change anything in that default dllmain.cpp file except for including my own version of pch.

The documentation for this warning (along with many VS2012 errors/warnings) is nowhere to be found on MSDN and here is the only relevant link I can find:

http://social.msdn.microsoft.com/Forums/en-US/vssetup/thread/6daa9587-fe54-4e84-a8b9-0e5c52c2f6e8/

and the op there didn't get an answer.

If anyone knows what it means and how to fix it, it would be great!

Answer 1

As far as I can tell, you can safely ignore the warning. The compiler cribs when it sees a Win32-style DllMain being compiled using the /ZW flag (Consume Windows Runtime Extensions). However, the function gets called as you'd normally expect.

Alternatively, you can work around the warning by compiling dllmain.cpp without /ZW. You might need to adjust the PCH settings for this to properly work. This is the path taken by the DLL (Windows Store apps) C++/CX project template in Visual Studio.

Incidentally, the reason you do not get the warning when you're trying to build a Windows Runtime Component project (which builds everything using /ZW) is that a Windows Runtime Component doesn't declare a DllMain. This is not to say that it can't; it just picks up the dummy DllMain that the CRT defines (which basically turns off per-thread initialization and reports success).