# SDL_realloc_func A callback used to implement [SDL_realloc](SDL_realloc)(). ## Header File Defined in [<SDL3/SDL_stdinc.h>](https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_stdinc.h) ## Syntax ```c typedef void *(SDLCALL *SDL_realloc_func)(void *mem, size_t size); ``` ## Function Parameters | | | | -------- | ----------------------------------------------------- | | **mem** | a pointer to allocated memory to reallocate, or NULL. | | **size** | the new size of the memory. | ## Return Value Returns a pointer to the newly allocated memory, or NULL if allocation failed. ## Remarks SDL will always ensure that the passed `size` is greater than 0. ## Thread Safety It should be safe to call this callback from any thread. ## Version This datatype is available since SDL 3.2.0. ## See Also - [SDL_realloc](SDL_realloc) - [SDL_GetOriginalMemoryFunctions](SDL_GetOriginalMemoryFunctions) - [SDL_GetMemoryFunctions](SDL_GetMemoryFunctions) - [SDL_SetMemoryFunctions](SDL_SetMemoryFunctions) ---- [CategoryAPI](CategoryAPI), [CategoryAPIDatatype](CategoryAPIDatatype), [CategoryStdinc](CategoryStdinc)