Added handling of NULL as input for SDL_GameControllerAddMapping().
diff --git a/src/joystick/SDL_gamecontroller.c b/src/joystick/SDL_gamecontroller.c
index 76b9b06..633a23c 100644
--- a/src/joystick/SDL_gamecontroller.c
+++ b/src/joystick/SDL_gamecontroller.c
@@ -669,6 +669,10 @@ SDL_GameControllerAddMapping(const char *mappingString)
ControllerMapping_t *pControllerMapping;
SDL_bool is_xinput_mapping = SDL_FALSE;
+ if (!mappingString) {
+ return SDL_InvalidParamError("mappingString");
+ }
+
pchGUID = SDL_PrivateGetControllerGUIDFromMappingString(mappingString);
if (!pchGUID) {
return SDL_SetError("Couldn't parse GUID from %s", mappingString);