The SDL_PixelFormat* passed to SDL_ConvertSurface() should be const.
diff --git a/include/SDL_surface.h b/include/SDL_surface.h
index 4062012..e18153a 100644
--- a/include/SDL_surface.h
+++ b/include/SDL_surface.h
@@ -357,7 +357,7 @@ extern DECLSPEC void SDLCALL SDL_GetClipRect(SDL_Surface * surface,
* surface.
*/
extern DECLSPEC SDL_Surface *SDLCALL SDL_ConvertSurface
- (SDL_Surface * src, SDL_PixelFormat * fmt, Uint32 flags);
+ (SDL_Surface * src, const SDL_PixelFormat * fmt, Uint32 flags);
extern DECLSPEC SDL_Surface *SDLCALL SDL_ConvertSurfaceFormat
(SDL_Surface * src, Uint32 pixel_format, Uint32 flags);
diff --git a/src/video/SDL_surface.c b/src/video/SDL_surface.c
index 84d3a4d..1c4631c 100644
--- a/src/video/SDL_surface.c
+++ b/src/video/SDL_surface.c
@@ -801,7 +801,7 @@ SDL_UnlockSurface(SDL_Surface * surface)
* Convert a surface into the specified pixel format.
*/
SDL_Surface *
-SDL_ConvertSurface(SDL_Surface * surface, SDL_PixelFormat * format,
+SDL_ConvertSurface(SDL_Surface * surface, const SDL_PixelFormat * format,
Uint32 flags)
{
SDL_Surface *convert;