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

# wcswidth(3)

determine columns needed for a fixed-size wide-character string

## NAME

wcswidth - determine columns needed for a fixed-size wide-character string

## LIBRARY

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

## SYNOPSIS

```
#define _XOPEN_SOURCE             /* See feature_test_macros(7) */
#include <wchar.h>
```

**int wcswidth(const wchar\_t \****s***, size\_t** *n***);**

## DESCRIPTION

The **wcswidth**() function returns the number of columns needed to represent the wide-character string pointed to by *s*, but at most *n* wide characters. If a nonprintable wide character occurs among these characters, -1 is returned.

## RETURN VALUE

The **wcswidth**() function returns the number of column positions for the wide-character string *s*, truncated to at most length *n*.

## ATTRIBUTES

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

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

## STANDARDS

POSIX.1-2008.

## HISTORY

POSIX.1-2001.

## NOTES

The behavior of **wcswidth**() depends on the **LC\_CTYPE** category of the current locale.

## SEE ALSO

[**iswprint**(3)](/iswprint/3.md), [**wcwidth**(3)](/wcwidth/3.md)