---
name: "SDL_strlwr"
section: "3"
platform: "linux"
package: "libsdl3-doc"
version: "3.2.10+ds-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/SDL_strlwr"
---

# SDL\_strlwr(3)

Convert a string to lowercase.

## NAME

SDL\_strlwr - Convert a string to lowercase.

## HEADER FILE

Defined in SDL3/SDL\_stdinc.h

## SYNOPSIS

```
#include "SDL3/SDL.h"
```

**char \* SDL\_strlwr(char \*str);**

## DESCRIPTION

**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.

## FUNCTION PARAMETERS

- *str*

  the string to convert in-place. Can not be NULL.

## RETURN VALUE

Returns the **str** pointer passed into this function.

## THREAD SAFETY

It is safe to call this function from any thread.

## AVAILABILITY

This function is available since SDL 3.2.0.

## SEE ALSO

**•**(3), [**SDL\_strupr**(3)](/SDL_strupr/3.md)