MIDL and juce_Initialisation.h interaction

Windows
1

Hi Jules,

It seems that when a VS2012 project uses the MIDL compiler, because there is an .idl file ( you know, to define COM classes and interfaces), the prototype of WinMain that the compiler expects is:

int __stdcall WinMain (HINSTANCE, HINSTANCE, const LPSTR, int)

instead of:

int __stdcall WinMain (void*, void*, const char*, int)

I got this conclusion because the VS2012 c++ compiler complains showing C2733 (second C linkage of overloaded function ‘function’ not allowed) and C2731 (The function WinMain cannot be overloaded.) errors.

I was diving into juce_Initialisation.h and I discovered that in the #IF DEFINE nest:

#if JUCE_WINDOWS #if defined (WINAPI) || defined (_WINDOWS_) #define JUCE_MAIN_FUNCTION int __stdcall WinMain (HINSTANCE, HINSTANCE, const LPSTR, int) #elif defined (_UNICODE) #define JUCE_MAIN_FUNCTION int __stdcall WinMain (void*, void*, const wchar_t*, int) #else #define JUCE_MAIN_FUNCTION int __stdcall WinMain (void*, void*, const char*, int) #endif #define JUCE_MAIN_FUNCTION_ARGS #else #define JUCE_MAIN_FUNCTION int main (int argc, char* argv[]) #define JUCE_MAIN_FUNCTION_ARGS argc, (const char**) argv #endif

reachs that WINAPI or WINDOWS is not defined. So JUCE_MAIN_FUNCTION is defined as int __stdcall WinMain (void*, void*, const char*, int) what the compiler not expect.

I’ve solved it temporally bypassing all the #if segment code and hardcoding the WinMain that the compiler expects: int __stdcall WinMain (HINSTANCE, HINSTANCE, const LPSTR, int)
But I think you can fix it to be compatible with the #IF DEFINE code

Gabriel

2

You could work around this without any hacks by just defining WINAPI in your AppConfig.h, right?

Otherwise, if your build doesn’t have either WINDOWS or WINAPI defined (which seems a bit odd…) then I’d need to know what it does have defined in order to extend that #if statement.

3

Jules,

I’ve solved it. In main.cpp, I swapped these lines generated by introjucer:

#include "MainComponent.h" #include "../JuceLibraryCode/JuceHeader.h"

Then, WINAPI is declared before juce_Initialisation.h uses it.

Does it make sense to you?

4

No, that’s not a very good idea. If you need to include windows.h, then you should do it before JuceHeader.h, but you should still include JuceHeader.h before your MainComponent.h.

5

All right! Definitely agree.
Thank you, Jules.