PortNintendo 3DS SDL_main to header-only + SDL_N3DSRunApp()

and move the #undef main and #define main SDL_main to the start/end of
SDL_main_impl.h instead of repeating it in every platform implementation

Thanks to SDL_N3DSRunApp we don't need the #include <3ds.h> in
SDL_main_impl.h - that caused conflicts with testthread.c, because both
have (different) ThreadFunc typedefs.

CMakeLists.txt

@@ -2688,6 +2688,9 @@ elseif(N3DS)
   file(GLOB N3DS_MAIN_SOURCES ${SDL3_SOURCE_DIR}/src/main/n3ds/*.c)
   set(SDLMAIN_SOURCES ${SDLMAIN_SOURCES} ${N3DS_MAIN_SOURCES})
 
+  file(GLOB N3DS_CORE_SOURCES ${SDL3_SOURCE_DIR}/src/core/n3ds/*.c)
+  list(APPEND SOURCE_FILES ${N3DS_CORE_SOURCES})
+
   if(SDL_AUDIO)
     set(SDL_AUDIO_DRIVER_N3DS 1)
     file(GLOB N3DS_AUDIO_SOURCES ${SDL3_SOURCE_DIR}/src/audio/n3ds/*.c)

include/SDL3/SDL_main.h

@@ -278,6 +278,22 @@ extern DECLSPEC void SDLCALL SDL_GDKSuspendComplete(void);
 
 #endif /* __GDK__ */
 
+#ifdef __3DS__
+
+/**
+ * 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(), an SDL_main_func
+ * \return the return value from mainFunction
+ *
+ * \since This function is available since SDL 3.0.0.
+ */
+extern DECLSPEC int SDLCALL SDL_N3DSRunApp(int argc, char *argv[], SDL_main_func mainFunction);
+
+#endif /* __3DS__ */
+
 #ifdef __cplusplus
 }
 #endif
@@ -286,7 +302,8 @@ extern DECLSPEC void SDLCALL SDL_GDKSuspendComplete(void);
 
 #if !defined(SDL_MAIN_HANDLED) && !defined(SDL_MAIN_NOIMPL)
 /* include header-only SDL_main implementations */
-#if defined(__WIN32__) || defined(__GDK__) || defined(__IOS__) || defined(__TVOS__) /* TODO: other platforms */
+#if defined(__WIN32__) || defined(__GDK__) || defined(__IOS__) || defined(__TVOS__) \
+    || defined(__3DS__) /* TODO: other platforms */
 #include <SDL3/SDL_main_impl.h>
 #elif defined(__WINRT__) /* TODO: other C++ platforms */
 

include/SDL3/SDL_main_impl.h

@@ -35,6 +35,12 @@
    and main() is implemented in plain C */
 #if !defined(SDL_MAIN_HANDLED) && !defined(SDL_MAIN_NOIMPL)
 
+/* the implementations below must be able to use the implement real main(), nothing renamed
+   (the user's main() will be renamed to SDL_main so it can be called from here) */
+#ifdef main
+#  undef main
+#endif /* main */
+
 #if defined(__WIN32__) || defined(__GDK__)
 
 /* these defines/typedefs are needed for the WinMain() definition */
@@ -42,10 +48,6 @@
 #define WINAPI __stdcall
 #endif
 
-#ifdef main
-#  undef main
-#endif /* main */
-
 #include <SDL3/begin_code.h>
 
 #ifdef __cplusplus
@@ -102,9 +104,6 @@ WinMain(HINSTANCE hInst, HINSTANCE hPrev, LPSTR szCmdLine, int sw)
 
 #include <SDL3/close_code.h>
 
-/* rename users main() function to SDL_main() so it can be called from the wrapper above */
-#define main    SDL_main
-
 /* end of __WIN32__ and __GDK__ impls */
 #elif defined(__WINRT__)
 
@@ -163,10 +162,6 @@ int CALLBACK WinMain(HINSTANCE, HINSTANCE, LPSTR, int)
 /* end of WinRT impl */
 #elif defined(__IOS__) || defined(__TVOS__)
 
-#ifdef main
-#  undef main
-#endif /* main */
-
 #include <SDL3/begin_code.h>
 
 #ifdef __cplusplus
@@ -184,15 +179,35 @@ int main(int argc, char *argv[])
 
 #include <SDL3/close_code.h>
 
-/* rename users main() function to SDL_main() so it can be called from the wrapper above */
-#define main    SDL_main
-
 /* end of __IOS__ and __TVOS__ impls */
+#elif defined(__3DS__)
+
+#include <SDL3/begin_code.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+int main(int argc, char *argv[])
+{
+    return SDL_N3DSRunApp(argc, argv, SDL_main);
+}
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#include <SDL3/close_code.h>
+
+/* end of __3DS__ impl */
 
 /* TODO: remaining platforms */
 
 #endif /* __WIN32__ etc */
 
+/* rename users main() function to SDL_main() so it can be called from the wrappers above */
+#define main    SDL_main
+
 #endif /* SDL_MAIN_HANDLED */
 
 #endif /* SDL_main_windows_h_ */

src/core/n3ds/SDL_n3ds.c

@@ -0,0 +1,49 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2022 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.
+*/
+
+#include "SDL_internal.h"
+
+#ifdef __3DS__
+
+#include <3ds.h>
+
+DECLSPEC int
+SDL_N3DSRunApp(int argc, char *argv[], SDL_main_func mainFunction)
+{
+    int result;
+    /* init */
+    osSetSpeedupEnable(true);
+    romfsInit();
+
+    SDL_SetMainReady();
+    result = mainFunction(argc, argv);
+
+    /* quit */
+    romfsExit();
+
+    return result;
+}
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif

src/dynapi/SDL_dynapi_overrides.h

@@ -886,3 +886,4 @@
 #define SDL_GetEventState SDL_GetEventState_REAL
 #define SDL_GetRenderDriver SDL_GetRenderDriver_REAL
 #define SDL_Win32RunApp SDL_Win32RunApp_REAL
+#define SDL_N3DSRunApp SDL_N3DSRunApp_REAL

src/dynapi/SDL_dynapi_procs.h

@@ -964,3 +964,6 @@ SDL_DYNAPI_PROC(const char*,SDL_GetRenderDriver,(int a),(a),return)
 #if defined(__WIN32__)
 SDL_DYNAPI_PROC(int,SDL_Win32RunApp,(SDL_main_func a, void *b),(a,b),return)
 #endif
+#if defined(__3DS__)
+SDL_DYNAPI_PROC(int,SDL_N3DSRunApp,(int a, char *b[], SDL_main_func c),(a,b,c),return)
+#endif

src/main/n3ds/SDL_n3ds_main.c

@@ -17,44 +17,9 @@
   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.
-*/
-#include <SDL3/SDL.h>
-#include <SDL3/SDL_main.h> /* until this SDL_main impl is converted to header-only.. */
-
-#ifdef __3DS__
-
-#include <3ds.h>
-
-#ifdef main
-#undef main
-#endif
-
-SDL_FORCE_INLINE void N3DS_Init(void);
-SDL_FORCE_INLINE void N3DS_Quit(void);
 
-int main(int argc, char *argv[])
-{
-    int result;
-    N3DS_Init();
-    SDL_SetMainReady();
-    result = SDL_main(argc, argv);
-    N3DS_Quit();
-    return result;
-}
-
-SDL_FORCE_INLINE void
-N3DS_Init(void)
-{
-    osSetSpeedupEnable(true);
-    romfsInit();
-}
-
-SDL_FORCE_INLINE void
-N3DS_Quit(void)
-{
-    romfsExit();
-}
-
-#endif /* __3DS__ */
+   Nothing to do here, the code moved into SDL_main_impl.h
+    TODO: remove this file
+*/
 
 /* vi: set sts=4 ts=4 sw=4 expandtab: */