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

# MB\_LEN\_MAX(3)

maximum multibyte length of a character across all locales

## NAME

MB\_LEN\_MAX - maximum multibyte length of a character across all locales

## LIBRARY

Standard C library (*libc*)

## SYNOPSIS

```
#include <limits.h>
```

## DESCRIPTION

The **MB\_LEN\_MAX** macro is the maximum number of bytes needed to represent a single wide character, in any of the supported locales.

## RETURN VALUE

A constant integer greater than zero.

## STANDARDS

C11, POSIX.1-2008.

## HISTORY

C99, POSIX.1-2001.

## NOTES

The entities **MB\_LEN\_MAX** and *sizeof(wchar\_t)* are totally unrelated. In glibc, **MB\_LEN\_MAX** is typically 16 (6 in glibc versions earlier than 2.2), while *sizeof(wchar\_t)* is 4.

## SEE ALSO

[**MB\_CUR\_MAX**(3)](/MB_CUR_MAX/3.md)