SDL/include/SDL3/SDL_main.h

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2023 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

#ifndef SDL_main_h_
#define SDL_main_h_

#include <SDL3/SDL_stdinc.h>

/**
 *  \file SDL_main.h
 *
 *  \brief Redefine main() on some platforms so that it is called by SDL.
 */

#ifndef SDL_MAIN_HANDLED
#ifdef __WIN32__
/* On Windows SDL provides WinMain(), which parses the command line and passes
   the arguments to your main function.

   If you provide your own WinMain(), you may define SDL_MAIN_HANDLED
 */
#define SDL_MAIN_AVAILABLE

#elif defined(__WINRT__)
/* On WinRT, SDL provides a main function that initializes CoreApplication,
   creating an instance of IFrameworkView in the process.

   Ideally, #include'ing SDL_main.h is enough to get a main() function working.
   However, that requires the source file your main() is in to be compiled
   as C++ *and* with the /ZW compiler flag. If that's not feasible, add an
   otherwise empty .cpp file that only contains `#include <SDL3/SDL_main.h>`
   and build that with /ZW (still include SDL_main.h in your other file with main()!).
   In XAML apps, instead the function SDL_RunApp() must be called with a pointer
   to the Direct3D-hosted XAML control passed in as the "reserved" argument.
*/
#define SDL_MAIN_NEEDED

#elif defined(__GDK__)
/* On GDK, SDL provides a main function that initializes the game runtime.

   If you prefer to write your own WinMain-function instead of having SDL
   provide one that calls your main() function,
   #define SDL_MAIN_HANDLED before #include'ing SDL_main.h
   and call the SDL_RunApp function from your entry point.
*/
#define SDL_MAIN_NEEDED

#elif defined(__IOS__)
/* On iOS SDL provides a main function that creates an application delegate
   and starts the iOS application run loop.

   To use it, just #include SDL_main.h in the source file that contains your
   main() function.

   See src/video/uikit/SDL_uikitappdelegate.m for more details.
 */
#define SDL_MAIN_NEEDED

#elif defined(__ANDROID__)
/* On Android SDL provides a Java class in SDLActivity.java that is the
   main activity entry point.

   See docs/README-android.md for more details on extending that class.
 */
#define SDL_MAIN_NEEDED

/* We need to export SDL_main so it can be launched from Java */
#define SDLMAIN_DECLSPEC    DECLSPEC

#elif defined(__PSP__)
/* On PSP SDL provides a main function that sets the module info,
   activates the GPU and starts the thread required to be able to exit
   the software.

   If you provide this yourself, you may define SDL_MAIN_HANDLED
 */
#define SDL_MAIN_AVAILABLE

#elif defined(__PS2__)
#define SDL_MAIN_AVAILABLE

#define SDL_PS2_SKIP_IOP_RESET() \
   void reset_IOP(); \
   void reset_IOP() {}

#elif defined(__3DS__)
/*
  On N3DS, SDL provides a main function that sets up the screens
  and storage.

  If you provide this yourself, you may define SDL_MAIN_HANDLED
*/
#define SDL_MAIN_AVAILABLE

#elif defined(__NGAGE__)

/*
   TODO: not sure if it should be SDL_MAIN_NEEDED, in SDL2 ngage had a
        main implementation, but wasn't mentioned in SDL_main.h
 */
#define SDL_MAIN_AVAILABLE

#endif
#endif /* SDL_MAIN_HANDLED */

#ifndef SDLMAIN_DECLSPEC
#define SDLMAIN_DECLSPEC
#endif

/**
 *  \file SDL_main.h
 *
 *  The application's main() function must be called with C linkage,
 *  and should be declared like this:
 *  \code
 *  #ifdef __cplusplus
 *  extern "C"
 *  #endif
 *  int main(int argc, char *argv[])
 *  {
 *  }
 *  \endcode
 */

#if defined(SDL_MAIN_NEEDED) || defined(SDL_MAIN_AVAILABLE)
#define main    SDL_main
#endif

#include <SDL3/SDL_begin_code.h>
#ifdef __cplusplus
extern "C" {
#endif

/**
 *  The prototype for the application's main() function
 */
typedef int (*SDL_main_func)(int argc, char *argv[]);
extern SDLMAIN_DECLSPEC int SDL_main(int argc, char *argv[]);


/**
 * Circumvent failure of SDL_Init() when not using SDL_main() as an entry
 * point.
 *
 * This function is defined in SDL_main.h, along with the preprocessor rule to
 * redefine main() as SDL_main(). Thus to ensure that your main() function
 * will not be changed it is necessary to define SDL_MAIN_HANDLED before
 * including SDL.h.
 *
 * \since This function is available since SDL 3.0.0.
 *
 * \sa SDL_Init
 */
extern DECLSPEC void SDLCALL SDL_SetMainReady(void);

/**
 * Initializes and launches an SDL application, by doing platform-specific
 * initialization before calling your mainFunction and cleanups after it
 * returns, if that is needed for a specific platform, otherwise it just calls
 * mainFunction.
 *
 * You can use this if you want to use your own main() implementation without
 * using SDL_main (like when using SDL_MAIN_HANDLED). When using this, you do
 * *not* need SDL_SetMainReady().
 *
 * \param argc The argc parameter from the application's main() function, or 0
 *             if the platform's main-equivalent has no argc
 * \param argv The argv parameter from the application's main() function, or
 *             NULL if the platform's main-equivalent has no argv
 * \param mainFunction Your SDL app's C-style main(), an SDL_main_func. NOT
 *                     the function you're calling this from! Its name doesn't
 *                     matter, but its signature must be like int my_main(int
 *                     argc, char* argv[])
 * \param reserved should be NULL (reserved for future use, will probably be
 *                 platform-specific then)
 * \returns the return value from mainFunction: 0 on success, -1 on failure;
 *          SDL_GetError() might have more information on the failure
 *
 * \since This function is available since SDL 3.0.0.
 */
extern DECLSPEC int SDLCALL SDL_RunApp(int argc, char* argv[], SDL_main_func mainFunction, void * reserved);

#if defined(__WIN32__) || defined(__GDK__)

/**
 * Register a win32 window class for SDL's use.
 *
 * This can be called to set the application window class at startup. It is
 * safe to call this multiple times, as long as every call is eventually
 * paired with a call to SDL_UnregisterApp, but a second registration attempt
 * while a previous registration is still active will be ignored, other than
 * to increment a counter.
 *
 * Most applications do not need to, and should not, call this directly; SDL
 * will call it when initializing the video subsystem.
 *
 * \param name the window class name, in UTF-8 encoding. If NULL, SDL
 *             currently uses "SDL_app" but this isn't guaranteed.
 * \param style the value to use in WNDCLASSEX::style. If `name` is NULL, SDL
 *              currently uses `(CS_BYTEALIGNCLIENT | CS_OWNDC)` regardless of
 *              what is specified here.
 * \param hInst the HINSTANCE to use in WNDCLASSEX::hInstance. If zero, SDL
 *              will use `GetModuleHandle(NULL)` instead.
 * \returns 0 on success or a negative error code on failure; call
 *          SDL_GetError() for more information.
 *
 * \since This function is available since SDL 3.0.0.
 */
extern DECLSPEC int SDLCALL SDL_RegisterApp(const char *name, Uint32 style, void *hInst);

/**
 * Deregister the win32 window class from an SDL_RegisterApp call.
 *
 * This can be called to undo the effects of SDL_RegisterApp.
 *
 * Most applications do not need to, and should not, call this directly; SDL
 * will call it when deinitializing the video subsystem.
 *
 * It is safe to call this multiple times, as long as every call is eventually
 * paired with a prior call to SDL_RegisterApp. The window class will only be
 * deregistered when the registration counter in SDL_RegisterApp decrements to
 * zero through calls to this function.
 *
 * \since This function is available since SDL 3.0.0.
 */
extern DECLSPEC void SDLCALL SDL_UnregisterApp(void);

#endif /* defined(__WIN32__) || defined(__GDK__) */


#ifdef __WINRT__

/* for compatibility with SDL2's function of this name */
#define SDL_WinRTRunApp(MAIN_FUNC, RESERVED)  SDL_RunApp(0, NULL, MAIN_FUNC, RESERVED)

#endif /* __WINRT__ */

#ifdef __IOS__

/* for compatibility with SDL2's function of this name */
#define SDL_UIKitRunApp(ARGC, ARGV, MAIN_FUNC)  SDL_RunApp(ARGC, ARGV, MAIN_FUNC, NULL)

#endif /* __IOS__ */

#ifdef __GDK__

/* for compatibility with SDL2's function of this name */
#define SDL_GDKRunApp(MAIN_FUNC, RESERVED)  SDL_RunApp(0, NULL, MAIN_FUNC, RESERVED)

/**
 * Callback from the application to let the suspend continue.
 *
 * \since This function is available since SDL 3.0.0.
 */
extern DECLSPEC void SDLCALL SDL_GDKSuspendComplete(void);

#endif /* __GDK__ */

#ifdef __cplusplus
}
#endif

#include <SDL3/SDL_close_code.h>

#if !defined(SDL_MAIN_HANDLED) && !defined(SDL_MAIN_NOIMPL)
/* include header-only SDL_main implementations */
#if defined(__WIN32__) || defined(__GDK__) || defined(__IOS__) || defined(__TVOS__) \
    || defined(__3DS__) || defined(__NGAGE__) || defined(__PS2__) || defined(__PSP__)

/* platforms whichs main (-equivalent) can be implemented in plain C */
#include <SDL3/SDL_main_impl.h>

#elif defined(__WINRT__) /* C++ platforms */

#ifdef __cplusplus
#include <SDL3/SDL_main_impl.h>
#else
/* Note: to get rid of the following warning, you can #define SDL_MAIN_NOIMPL before including SDL_main.h
 *  in your C sourcefile that contains the standard main. Do *not* use SDL_MAIN_HANDLED for that, then SDL_main won't find your main()!
 */
#ifdef _MSC_VER
#pragma message("Note: Your platform needs the SDL_main implementation in a C++ source file. You can keep your main() in plain C (then continue including SDL_main.h there!) and create a fresh .cpp file that only contains #include <SDL3/SDL_main.h>")
#elif defined(__GNUC__) /* gcc, clang, mingw and compatible are matched by this and have #warning */
#warning "Note: Your platform needs the SDL_main implementation in a C++ source file. You can keep your main() in plain C and create a fresh .cpp file that only contains #include <SDL3/SDL_main.h>"
#endif /* __GNUC__ */
#endif /* __cplusplus */

#endif /* C++ platforms like __WINRT__ etc */

#endif /* SDL_MAIN_HANDLED */

#endif /* SDL_main_h_ */