Get the length and determine the validity of a multibyte character.
size_t _mbclen( const unsigned char *c );
int mblen( const char *mbstr, size_t count );
| Routine | Required Header | Compatibility |
| _mbclen | <mbstring.h> | Win 95, Win NT |
| mblen | <stdlib.h> | ANSI, Win 95, Win NT |
For additional compatibility information, see Compatibility in the Introduction.
Libraries
| LIBC.LIB | Single thread static library, retail version |
| LIBCMT.LIB | Multithread static library, retail version |
| MSVCRT.LIB | Import library for MSVCRT.DLL, retail version |
Return Value
_mbclen returns 1 or 2, according to whether the multibyte character c is one or two bytes long. There is no error return for _mbclen. If mbstr is not NULL, mblen returns the length, in bytes, of the multibyte character. If mbstr is NULL, or if it points to the wide-character null character, mblen returns 0. If the object that mbstr points to does not form a valid multibyte character within the first count characters, mblen returns –1.
Parameters
c
Multibyte character
mbstr
Address of multibyte-character byte sequence
count
Number of bytes to check
Remarks
The _mbclen function returns the length, in bytes, of the multibyte character c. If c does not point to the lead byte of a multibyte character as determined by an implicit call to _ismbblead, the result of _mbclen is unpredictable.
mblen returns the length in bytes of mbstr if it is a valid multibyte character. It examines count or fewer bytes contained in mbstr, but not more than MB_CUR_MAX bytes. mblen determines multibyte-character validity according to the LC_CTYPE category setting of the current locale. For more information on the LC_CTYPE category, see setlocale.
Generic-Text Routine Mappings
| TCHAR.H Routine | _UNICODE & _MBCS Not Defined | _MBCS Defined | _UNICODE Defined |
| _tclen | Maps to macro or inline function | _mbclen | Maps to macro or inline function |
Example
/* MBLEN.C illustrates the behavior of the mblen function
*/
#include <stdlib.h>
#include <stdio.h>
void main( void )
{
int i;
char *pmbc = (char *)malloc( sizeof( char ) );
wchar_t wc = L'a';
printf( "Convert wide character to multibyte character:\n" );
i = wctomb( pmbc, wc );
printf( "\tCharacters converted: %u\n", i );
printf( "\tMultibyte character: %x\n\n", pmbc );
i = mblen( pmbc, MB_CUR_MAX );
printf( "Length in bytes of multibyte character %x: %u\n", pmbc, i );
pmbc = NULL;
i = mblen( pmbc, MB_CUR_MAX );
printf( "Length in bytes of NULL multibyte character %x: %u\n", pmbc, i );
}
Output
Convert wide character to multibyte character:
Characters converted: 1
Multibyte character: 2c02cc
Length in bytes of multibyte character 2c02cc: 1
Length in bytes of NULL multibyte character 0: 0
Character Classification Routines | Locale Routines | Interpretation of Multibyte-Character Sequences