This documentation is archived and is not being maintained.

isleadbyte, _isleadbyte_l

Updated: May 2011

Indicates whether the first byte of the specified character is the lead byte of a multibyte character.

int isleadbyte(
   int c 
int _isleadbyte_l(
   int c, 
   _locale_t locale


A character to test. This parameter is expected to be a multibyte character whose type is int.


A locale, instead of the current locale, that governs this operation. For more information, see Locale.

A nonzero value if the first byte of the c parameter is the lead byte of a multibyte character; otherwise, zero. The return value is always zero in the "C" locale and in single-byte character set (SBCS) locales.

The isleadbyte and _isleadbyte_l functions test the result of casting parameter c to an unsigned char.

Generic-Text Routine Mappings

TCHAR.H routine

_UNICODE & _MBCS not defined

_MBCS defined

_UNICODE defined


Always returns false


Always returns false


Required header





For additional compatibility information, see Compatibility in the Introduction.




May 2011

Documented the "locale" parameter of _isleadbyte_l.

Information enhancement.