---
name: "wcslen"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/wcslen"
---

# wcslen(3)

determine the length of a wide-character string

## NAME

wcslen - determine the length of a wide-character string

## LIBRARY

Standard C library (*libc*, *-lc*)

## SYNOPSIS

```
#include <wchar.h>
```

**size\_t wcslen(const wchar\_t \****s***);**

## DESCRIPTION

The **wcslen**() function is the wide-character equivalent of the [**strlen**(3)](/strlen/3.md) function. It determines the length of the wide-character string pointed to by *s*, excluding the terminating null wide character (L'\\0').

## RETURN VALUE

The **wcslen**() function returns the number of wide characters in *s*.

## ATTRIBUTES

For an explanation of the terms used in this section, see [**attributes**(7)](/attributes/7.md).

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **wcslen**() | Thread safety | MT-Safe |

## STANDARDS

C11, POSIX.1-2008.

## HISTORY

POSIX.1-2001, C99.

## NOTES

In cases where the input buffer may not contain a terminating null wide character, [**wcsnlen**(3)](/wcsnlen/3.md) should be used instead.

## SEE ALSO

[**strlen**(3)](/strlen/3.md)