###### (This is the documentation for SDL3, which is the current stable version. [SDL2](https://wiki.libsdl.org/SDL2/) was the previous version!) # SDL_strlwr Convert a string to lowercase. ## Header File Defined in [](https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_stdinc.h) ## Syntax ```c char * SDL_strlwr(char *str); ``` ## Function Parameters | | | | | ------ | ------- | ------------------------------------------------ | | char * | **str** | the string to convert in-place. Can not be NULL. | ## Return Value (char *) Returns the `str` pointer passed into this function. ## Remarks **WARNING**: Regardless of system locale, this will only convert ASCII values 'A' through 'Z' to lowercase. This function operates on a null-terminated string of bytes--even if it is malformed UTF-8!--and converts ASCII characters 'A' through 'Z' to their lowercase equivalents in-place, returning the original `str` pointer. ## 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_strupr](SDL_strupr) ---- [CategoryAPI](CategoryAPI), [CategoryAPIFunction](CategoryAPIFunction), [CategoryStdinc](CategoryStdinc)