---
name: "wctomb"
section: "3"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/wctomb"
---

# wctomb(3)

convert a wide-character code to a character

## NAME

**wctomb** – convert a wide-character code to a character

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<stdlib.h\>**

*int*\

**wctomb**(*char \*mbchar*, *wchar\_t wchar*);

## DESCRIPTION

The **wctomb**() function converts a wide character *wchar* into a multibyte character and stores the result in *mbchar*. The object pointed to by *mbchar* must be large enough to accommodate the multibyte character, which may be up to MB\_LEN\_MAX bytes.

A call with a null *mbchar* pointer returns nonzero if the current locale requires shift states, zero otherwise; if shift states are required, the shift state is reset to the initial state.

## RETURN VALUES

If *mbchar* is NULL, the **wctomb**() function returns nonzero if shift states are supported, zero otherwise. If *mbchar* is valid, **wctomb**() returns the number of bytes processed in *mbchar*, or -1 if no multibyte character could be recognized or converted. In this case, **wctomb**(*Ns*, *'s*) internal conversion state is undefined.

## ERRORS

The **wctomb**() function will fail if:

- \[EILSEQ\]

  An invalid multibyte sequence was detected.

- \[EINVAL\]

  The internal conversion state is invalid.

## SEE ALSO

[mbtowc(3)](/mbtowc/3.md), [wcrtomb(3)](/wcrtomb/3.md), [wcstombs(3)](/wcstombs/3.md), [wctob(3)](/wctob/3.md)

## STANDARDS

The **wctomb**() function conforms to ISO/IEC 9899:1999 (“ISO C99”).