C in a Nutshell

Name

mblen

Synopsis

Determines the length of a multibyte character, or whether the multibyte encoding is stateful

#include <stdlib.h>
intmblen( const char *s, size_t maxsize );

The mblen() function determines the length in bytes of a multibyte character referenced by its pointer argument. If the argument points to a valid multibyte character, then mblen() returns a value greater than zero. If the argument points to a null character ('\0'), then mblen() returns 0. A return value of -1 indicates that the argument does not point to a valid multibyte character, or that the multibyte character is longer than the maximum size specified by the second argument. The LC_TYPE category in the current locale settings determines which byte sequences are valid multibyte characters.

The second argument specifies a maximum byte length for the multibyte character, and should not be greater than the value of the symbolic constant MB_CUR_MAX, defined in stdlib.h.

If you pass mblen() a null pointer as the first argument, then the return value indicates whether the current multibyte encoding is stateful. This behavior is the same as that of mbtowc(). If mblen() returns 0, then the encoding is stateless. If it returns any other value, the encoding is stateful; that is, the interpretation of a given byte sequence may depend on the shift state.

Example

size_t mbsrcat( char * restrict s1, char * restrict s2, mbstate_t * restrict p_s1state, size_t n ) /* mbsrcat: multibyte string restartable concatenation. * Appends ...