---
name: "SDL_tolower"
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_tolower"
---

# SDL\_tolower(3)

Convert low-ASCII English letters to lowercase.

## NAME

SDL\_tolower - Convert low-ASCII English letters to lowercase.

## HEADER FILE

Defined in SDL3/SDL\_stdinc.h

## SYNOPSIS

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

**int SDL\_tolower(int x);**

## DESCRIPTION

**WARNING** : Regardless of system locale, this will only convert ASCII values 'A' through 'Z' to lowercase.

This function returns the lowercase equivalent of **x** . If a character cannot be converted, or is already lowercase, this function returns **x** .

## FUNCTION PARAMETERS

- *x*

  character value to check.

## RETURN VALUE

Returns lowercase version of x, or x if no conversion available.

## THREAD SAFETY

It is safe to call this function from any thread.

## AVAILABILITY

This function is available since SDL 3.2.0.