SDL_WarpMouseGlobal() should return non-void.

There are platforms it isn't implemented on (and currently can't be
implemented on!), and there's currently no way for an app to know this.

This shouldn't break ABI on apps that moved to a revision between 2.0.3 and
2.0.4.

include/SDL_mouse.h

@@ -137,10 +137,11 @@ extern DECLSPEC void SDLCALL SDL_WarpMouseInWindow(SDL_Window * window,
  *
  *  \param x The x coordinate
  *  \param y The y coordinate
+ *  \return 0 on success, -1 on error (usually: unsupported by a platform).
  *
  *  \note This function generates a mouse motion event
  */
-extern DECLSPEC void SDLCALL SDL_WarpMouseGlobal(int x, int y);
+extern DECLSPEC int SDLCALL SDL_WarpMouseGlobal(int x, int y);
 
 /**
  *  \brief Set relative mouse mode.

src/dynapi/SDL_dynapi_procs.h

@@ -612,7 +612,7 @@ SDL_DYNAPI_PROC(int,SDL_WinRTRunApp,(int a, char **b, void *c),(a,b,c),return)
 SDL_DYNAPI_PROC(const wchar_t*,SDL_WinRTGetFSPathUNICODE,(SDL_WinRT_Path a),(a),return)
 SDL_DYNAPI_PROC(const char*,SDL_WinRTGetFSPathUTF8,(SDL_WinRT_Path a),(a),return)
 #endif
-SDL_DYNAPI_PROC(void,SDL_WarpMouseGlobal,(int a, int b),(a,b),)
+SDL_DYNAPI_PROC(int,SDL_WarpMouseGlobal,(int a, int b),(a,b),)
 SDL_DYNAPI_PROC(float,SDL_sqrtf,(float a),(a),return)
 SDL_DYNAPI_PROC(double,SDL_tan,(double a),(a),return)
 SDL_DYNAPI_PROC(float,SDL_tanf,(float a),(a),return)

src/events/SDL_mouse.c

@@ -535,14 +535,16 @@ SDL_WarpMouseInWindow(SDL_Window * window, int x, int y)
     }
 }
 
-void
+int
 SDL_WarpMouseGlobal(int x, int y)
 {
     SDL_Mouse *mouse = SDL_GetMouse();
 
     if (mouse->WarpMouseGlobal) {
-        mouse->WarpMouseGlobal(x, y);
+        return mouse->WarpMouseGlobal(x, y);
     }
+
+    return SDL_Unsupported();
 }
 
 static SDL_bool

src/events/SDL_mouse_c.h

@@ -61,7 +61,7 @@ typedef struct
     void (*WarpMouse) (SDL_Window * window, int x, int y);
 
     /* Warp the mouse to (x,y) in screen space */
-    void (*WarpMouseGlobal) (int x, int y);
+    int (*WarpMouseGlobal) (int x, int y);
 
     /* Set relative mode */
     int (*SetRelativeMouseMode) (SDL_bool enabled);

src/video/cocoa/SDL_cocoamouse.m

@@ -210,7 +210,7 @@ SDL_FindWindowAtPoint(const int x, const int y)
     return NULL;
 }
 
-static void
+static int
 Cocoa_WarpMouseGlobal(int x, int y)
 {
     SDL_Mouse *mouse = SDL_GetMouse();
@@ -219,7 +219,7 @@ Cocoa_WarpMouseGlobal(int x, int y)
         if ([data->listener isMoving]) {
             DLog("Postponing warp, window being moved.");
             [data->listener setPendingMoveX:x Y:y];
-            return;
+            return 0;
         }
     }
     const CGPoint point = CGPointMake((float)x, (float)y);
@@ -245,6 +245,8 @@ Cocoa_WarpMouseGlobal(int x, int y)
             SDL_SendMouseMotion(win, mouse->mouseID, 0, x - win->x, y - win->y);
         }
     }
+
+    return 0;
 }
 
 static void

src/video/mir/SDL_mirmouse.c

@@ -110,10 +110,10 @@ MIR_WarpMouse(SDL_Window* window, int x, int y)
     SDL_Unsupported();
 }
 
-static void
+static int
 MIR_WarpMouseGlobal(int x, int y)
 {
-    SDL_Unsupported();
+    return SDL_Unsupported();
 }
 
 static int

src/video/raspberry/SDL_rpimouse.c

@@ -216,18 +216,18 @@ RPI_WarpMouse(SDL_Window * window, int x, int y)
 }
 
 /* Warp the mouse to (x,y) */
-static void
+static int
 RPI_WarpMouseGlobal(int x, int y)
 {
     RPI_CursorData *curdata;
     DISPMANX_UPDATE_HANDLE_T update;
-    int ret;
     VC_RECT_T dst_rect;
     SDL_Mouse *mouse = SDL_GetMouse();
     
     if (mouse != NULL && mouse->cur_cursor != NULL && mouse->cur_cursor->driverdata != NULL) {
         curdata = (RPI_CursorData *) mouse->cur_cursor->driverdata;
         if (curdata->element != DISPMANX_NO_HANDLE) {
+            int ret;
             update = vc_dispmanx_update_start( 10 );
             SDL_assert( update );
             vc_dispmanx_rect_set( &dst_rect, x, y, curdata->w, curdata->h);
@@ -245,8 +245,11 @@ RPI_WarpMouseGlobal(int x, int y)
             /* Submit asynchronously, otherwise the peformance suffers a lot */
             ret = vc_dispmanx_update_submit( update, 0, NULL );
             SDL_assert( ret == DISPMANX_SUCCESS );
+            return (ret == DISPMANX_SUCCESS) ? 0 : -1;
         }
     }    
+
+    return -1;  /* !!! FIXME: this should SDL_SetError() somewhere. */
 }
 
 void

src/video/wayland/SDL_waylandmouse.c

@@ -347,10 +347,10 @@ Wayland_WarpMouse(SDL_Window *window, int x, int y)
     SDL_Unsupported();
 }
 
-static void
+static int
 Wayland_WarpMouseGlobal(int x, int y)
 {
-    SDL_Unsupported();
+    return SDL_Unsupported();
 }
 
 static int

src/video/windows/SDL_windowsmouse.c

@@ -236,7 +236,7 @@ WIN_WarpMouse(SDL_Window * window, int x, int y)
     SetCursorPos(pt.x, pt.y);
 }
 
-static void
+static int
 WIN_WarpMouseGlobal(int x, int y)
 {
     POINT pt;
@@ -244,6 +244,7 @@ WIN_WarpMouseGlobal(int x, int y)
     pt.x = x;
     pt.y = y;
     SetCursorPos(pt.x, pt.y);
+    return 0;
 }
 
 static int

src/video/x11/SDL_x11mouse.c

@@ -318,13 +318,14 @@ X11_WarpMouse(SDL_Window * window, int x, int y)
     X11_XSync(display, False);
 }
 
-static void
+static int
 X11_WarpMouseGlobal(int x, int y)
 {
     Display *display = GetDisplay();
 
     X11_XWarpPointer(display, None, DefaultRootWindow(display), 0, 0, 0, 0, x, y);
     X11_XSync(display, False);
+    return 0;
 }
 
 static int