How to cross-compile with SDL 2 from Linux for Windows

I tried to compile a simple C++ program that uses SDL 2 with the mingw-w64-g++ compiler on my Arch Linux (64bits).

For this I downloaded SDL2-devel-2.0.4-mingw.tar.gz from here

prog.cpp:

#include <SDL.h>

int main ()
{
    SDL_Init (SDL_INIT_VIDEO);

    SDL_Window *sdlWnd = SDL_CreateWindow ("Test", SDL_WINDOWPOS_UNDEFINED,
        SDL_WINDOWPOS_UNDEFINED, 800, 600, 0);

    SDL_Event event;
    bool running = true;

    while (running) {
        while (SDL_PollEvent (&event)) {
            if (event.type == SDL_QUIT) {
                running = false;
                break;
            }
        }
    }

    return 0;
}

Makefile:

GPP = x86_64-w64-mingw32-g++
prog.exe: prog.o
    $(GPP) -o prog.exe prog.o -LSDL2-2.0.4/lib/x64 -lSDL2main -lSDL2
prog.o: prog.cpp
    $(GPP) -o prog.o -c -ISDL2-2.0.4/include prog.cpp

Now making gives the error:

x86_64-w64-mingw32-g++ -o prog.exe prog.o -LSDL2-2.0.4/lib/x64 -lSDL2main -lSDL2
Warning: corrupt .drectve at end of def file
SDL2-2.0.4/lib/x64/SDL2main.lib(./x64/Release/SDL_windows_main.obj):(.text[main]+0x1c): undefined reference to `SDL_main'

Why undefined reference to `SDL_main’ ? Although I specified -lSDL2main ?

What did I do wrong? 🙁

Answer

Okay, it was because of the main functions signature, that has to be declared as:

int main(int argc, char *argv[])

according to the official SDL FAQ:

Make sure that you are declaring main() as:

#include "SDL.h"

int main(int argc, char *argv[])

You should be using main() instead of WinMain() even though you are creating a Windows application, because SDL provides a version of WinMain() which performs some SDL initialization before calling your main code. If for some reason you need to use WinMain(), take a look at the SDL source code in src/main/win32/SDL_main.c to see what kind of initialization you need to do in your WinMain() function so that SDL works properly.