Update SDL to 2.0.18

libs/SDL2/include/SDL_main.h

@@ -1,6 +1,6 @@
 /*
   Simple DirectMedia Layer
-  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
+  Copyright (C) 1997-2021 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
@@ -122,20 +122,62 @@ extern SDLMAIN_DECLSPEC int SDL_main(int argc, char *argv[]);
 
 
 /**
- *  This is called by the real SDL main function to let the rest of the
- *  library know that initialization was done properly.
+ * Circumvent failure of SDL_Init() when not using SDL_main() as an entry
+ * point.
  *
- *  Calling this yourself without knowing what you're doing can cause
- *  crashes and hard to diagnose problems with your application.
+ * 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 2.0.0.
+ *
+ * \sa SDL_Init
  */
 extern DECLSPEC void SDLCALL SDL_SetMainReady(void);
 
 #ifdef __WIN32__
 
 /**
- *  This can be called to set the application class at startup
+ * 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, -1 on error. SDL_GetError() may have details.
+ *
+ * \since This function is available since SDL 2.0.2.
+ */
+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 2.0.2.
  */
-extern DECLSPEC int SDLCALL SDL_RegisterApp(char *name, Uint32 style, void *hInst);
 extern DECLSPEC void SDLCALL SDL_UnregisterApp(void);
 
 #endif /* __WIN32__ */
@@ -144,12 +186,14 @@ extern DECLSPEC void SDLCALL SDL_UnregisterApp(void);
 #ifdef __WINRT__
 
 /**
- *  \brief Initializes and launches an SDL/WinRT application.
+ * Initialize and launch an SDL/WinRT application.
  *
- *  \param mainFunction The SDL app's C-style main().
- *  \param reserved Reserved for future use; should be NULL
- *  \return 0 on success, -1 on failure.  On failure, use SDL_GetError to retrieve more
- *      information on the failure.
+ * \param mainFunction the SDL app's C-style main(), an SDL_main_func
+ * \param reserved reserved for future use; should be NULL
+ * \returns 0 on success or -1 on failure; call SDL_GetError() to retrieve
+ *          more information on the failure.
+ *
+ * \since This function is available since SDL 2.0.3.
  */
 extern DECLSPEC int SDLCALL SDL_WinRTRunApp(SDL_main_func mainFunction, void * reserved);
 
@@ -158,12 +202,14 @@ extern DECLSPEC int SDLCALL SDL_WinRTRunApp(SDL_main_func mainFunction, void * r
 #if defined(__IPHONEOS__)
 
 /**
- *  \brief Initializes and launches an SDL application.
+ * Initializes and launches an SDL application.
  *
- *  \param argc The argc parameter from the application's main() function
- *  \param argv The argv parameter from the application's main() function
- *  \param mainFunction The SDL app's C-style main().
- *  \return the return value from mainFunction
+ * \param argc The argc parameter from the application's main() function
+ * \param argv The argv parameter from the application's main() function
+ * \param mainFunction The SDL app's C-style main(), an SDL_main_func
+ * \return the return value from mainFunction
+ *
+ * \since This function is available since SDL 2.0.10.
  */
 extern DECLSPEC int SDLCALL SDL_UIKitRunApp(int argc, char *argv[], SDL_main_func mainFunction);