---
name: "wcsstr"
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/wcsstr"
---

# wcsstr(3)

locate a substring in a wide-character string

## NAME

wcsstr - locate a substring in a wide-character string

## LIBRARY

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

## SYNOPSIS

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

**wchar\_t \*wcsstr(const wchar\_t \****haystack***, const wchar\_t \****needle***);**

## DESCRIPTION

The **wcsstr**() function is the wide-character equivalent of the [**strstr**(3)](/strstr/3.md) function. It searches for the first occurrence of the wide-character string *needle* (without its terminating null wide character (L'\\0')) as a substring in the wide-character string *haystack*.

## RETURN VALUE

The **wcsstr**() function returns a pointer to the first occurrence of *needle* in *haystack*. It returns NULL if *needle* does not occur as a substring in *haystack*.

Note the special case: If *needle* is the empty wide-character string, the return value is always *haystack* itself.

## ATTRIBUTES

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

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

## STANDARDS

C11, POSIX.1-2008.

## HISTORY

POSIX.1-2001, C99.

## SEE ALSO

[**strstr**(3)](/strstr/3.md), [**wcschr**(3)](/wcschr/3.md)