---
name: "SDL_utf8strlen"
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_utf8strlen"
---

# SDL\_utf8strlen(3)

Count the number of codepoints in a UTF-8 string.

## NAME

SDL\_utf8strlen - Count the number of codepoints in a UTF-8 string.

## HEADER FILE

Defined in SDL3/SDL\_stdinc.h

## SYNOPSIS

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

**size\_t SDL\_utf8strlen(const char \*str);**

## DESCRIPTION

Counts the \_codepoints\_, not \_bytes\_, in **str** , excluding the null terminator.

If you need to count the bytes in a string instead, consider using

**SDL\_strlen** ().

Since this handles Unicode, it expects the strings to be well-formed UTF-8 and not a null-terminated string of arbitrary bytes. Bytes that are not valid UTF-8 are treated as Unicode character U+FFFD (REPLACEMENT CHARACTER), so a malformed or incomplete UTF-8 sequence might increase the count by several replacement characters.

## FUNCTION PARAMETERS

- *str*

  The null-terminated UTF-8 string to read. Must not be NULL.

## RETURN VALUE

Returns The length (in codepoints, excluding the null terminator) of **src** .

## 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\_utf8strnlen**(3)](/SDL_utf8strnlen/3.md), **•**(3), [**SDL\_strlen**(3)](/SDL_strlen/3.md)