###### (This is the documentation for SDL3, which is the current stable version. [SDL2](https://wiki.libsdl.org/SDL2/) was the previous version!) # SDL_AddHintCallback Add a function to watch a particular hint. ## Header File Defined in [](https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_hints.h) ## Syntax ```c bool SDL_AddHintCallback(const char *name, SDL_HintCallback callback, void *userdata); ``` ## Function Parameters | | | | | ------------------------------------ | ------------ | ------------------------------------------------------------------------------------------------- | | const char * | **name** | the hint to watch. | | [SDL_HintCallback](SDL_HintCallback) | **callback** | An [SDL_HintCallback](SDL_HintCallback) function that will be called when the hint value changes. | | void * | **userdata** | a pointer to pass to the callback function. | ## Return Value (bool) Returns true on success or false on failure; call [SDL_GetError](SDL_GetError)() for more information. ## Remarks The callback function is called _during_ this function, to provide it an initial value, and again each time the hint's value changes. ## Thread Safety It is safe to call this function from any thread. ## Version This function is available since SDL 3.1.3. ## See Also - [SDL_RemoveHintCallback](SDL_RemoveHintCallback) ---- [CategoryAPI](CategoryAPI), [CategoryAPIFunction](CategoryAPIFunction), [CategoryHints](CategoryHints)