Added support for building SDL as a dynamic library on iOS

include/SDL_main.h

@@ -55,6 +55,10 @@
 /* On iOS SDL provides a main function that creates an application delegate
    and starts the iOS application run loop.
 
+   If you link with SDL dynamically on iOS, the main function can't be in a
+   shared library, so you need to link with libSDLmain.a, which includes a
+   stub main function that calls into the shared library to start execution.
+
    See src/video/uikit/SDL_uikitappdelegate.m for more details.
  */
 #define SDL_MAIN_NEEDED
@@ -114,6 +118,7 @@
 /**
  *  The prototype for the application's main() function
  */
+typedef C_LINKAGE SDLMAIN_DECLSPEC int (*SDL_main_func)(int argc, char *argv[]);
 extern C_LINKAGE SDLMAIN_DECLSPEC int SDL_main(int argc, char *argv[]);
 
 
@@ -136,8 +141,7 @@ extern DECLSPEC void SDLCALL SDL_SetMainReady(void);
 /**
  *  This can be called to set the application class at startup
  */
-extern DECLSPEC int SDLCALL SDL_RegisterApp(char *name, Uint32 style,
-                                            void *hInst);
+extern DECLSPEC int SDLCALL SDL_RegisterApp(char *name, Uint32 style, void *hInst);
 extern DECLSPEC void SDLCALL SDL_UnregisterApp(void);
 
 #endif /* __WIN32__ */
@@ -153,10 +157,24 @@ extern DECLSPEC void SDLCALL SDL_UnregisterApp(void);
  *  \return 0 on success, -1 on failure.  On failure, use SDL_GetError to retrieve more
  *      information on the failure.
  */
-extern DECLSPEC int SDLCALL SDL_WinRTRunApp(int (*mainFunction)(int, char **), void * reserved);
+extern DECLSPEC int SDLCALL SDL_WinRTRunApp(SDL_main_func mainFunction, void * reserved);
 
 #endif /* __WINRT__ */
 
+#if defined(__IPHONEOS__)
+
+/**
+ *  \brief 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
+ */
+extern DECLSPEC int SDLCALL SDL_UIKitRunApp(int argc, char *argv[], SDL_main_func mainFunction);
+
+#endif /* __IPHONEOS__ */
+
 
 #ifdef __cplusplus
 }

src/core/winrt/SDL_winrtapp_common.cpp

@@ -29,7 +29,7 @@
 int (*WINRT_SDLAppEntryPoint)(int, char **) = NULL;
 
 extern "C" DECLSPEC int
-SDL_WinRTRunApp(int (*mainFunction)(int, char **), void * xamlBackgroundPanel)
+SDL_WinRTRunApp(SDL_main_func mainFunction, void * xamlBackgroundPanel)
 {
     if (xamlBackgroundPanel) {
         return SDL_WinRTInitXAMLApp(mainFunction, xamlBackgroundPanel);
@@ -63,4 +63,4 @@ SDL_WinRTGetDeviceFamily()
 #endif
 
     return SDL_WINRT_DEVICEFAMILY_UNKNOWN;
-}
+}

src/dynapi/SDL_dynapi_overrides.h

@@ -713,3 +713,4 @@
 #define SDL_RenderCopyF SDL_RenderCopyF_REAL
 #define SDL_RenderCopyExF SDL_RenderCopyExF_REAL
 #define SDL_GetTouchDeviceType SDL_GetTouchDeviceType_REAL
+#define SDL_UIKitRunApp SDL_UIKitRunApp_REAL

src/dynapi/SDL_dynapi_procs.h

@@ -767,3 +767,6 @@ SDL_DYNAPI_PROC(int,SDL_RenderFillRectsF,(SDL_Renderer *a, const SDL_FRect *b, i
 SDL_DYNAPI_PROC(int,SDL_RenderCopyF,(SDL_Renderer *a, SDL_Texture *b, const SDL_Rect *c, const SDL_FRect *d),(a,b,c,d),return)
 SDL_DYNAPI_PROC(int,SDL_RenderCopyExF,(SDL_Renderer *a, SDL_Texture *b, const SDL_Rect *c, const SDL_FRect *d, const double e, const SDL_FPoint *f, const SDL_RendererFlip g),(a,b,c,d,e,f,g),return)
 SDL_DYNAPI_PROC(SDL_TouchDeviceType,SDL_GetTouchDeviceType,(SDL_TouchID a),(a),return)
+#ifdef __IPHONEOS__
+SDL_DYNAPI_PROC(int,SDL_UIKitRunApp,(int a, char *b, SDL_main_func c),(a,b,c),return)
+#endif

src/main/uikit/SDL_uikit_main.c

@@ -0,0 +1,19 @@
+/*
+    SDL_uiki_main.c, placed in the public domain by Sam Lantinga  3/18/2019
+*/
+#include "../../SDL_internal.h"
+
+/* Include the SDL main definition header */
+#include "SDL_main.h"
+
+#ifdef main
+#undef main
+#endif
+
+int
+main(int argc, char *argv[])
+{
+    return SDL_UIKitRunApp(argc, argv, SDL_main);
+}
+
+/* vi: set ts=4 sw=4 expandtab: */

src/video/uikit/SDL_uikitappdelegate.m

@@ -38,15 +38,25 @@
 #undef main
 #endif
 
+static SDL_main_func forward_main;
 static int forward_argc;
 static char **forward_argv;
 static int exit_status;
 
-int main(int argc, char **argv)
+#if defined(SDL_MAIN_NEEDED) && !defined(IOS_DYLIB)
+/* SDL is being built as a static library, include main() */
+int main(int argc, char *argv[])
+{
+	return SDL_UIKitRunApp(argc, argv, SDL_main);
+}
+#endif /* SDL_MAIN_NEEDED && !IOS_DYLIB */
+
+int SDL_UIKitRunApp(int argc, char *argv[], SDL_main_func mainFunction)
 {
     int i;
 
     /* store arguments */
+	forward_main = mainFunction;
     forward_argc = argc;
     forward_argv = (char **)malloc((argc+1) * sizeof(char *));
     for (i = 0; i < argc; i++) {
@@ -344,7 +354,7 @@ SDL_LoadLaunchImageNamed(NSString *name, int screenh)
 
     /* run the user's application, passing argc and argv */
     SDL_iPhoneSetEventPump(SDL_TRUE);
-    exit_status = SDL_main(forward_argc, forward_argv);
+    exit_status = forward_main(forward_argc, forward_argv);
     SDL_iPhoneSetEventPump(SDL_FALSE);
 
     if (launchWindow) {