Visual Studio 6.0

int isleadbyte( int c );

Routine Required Header Compatibility
isleadbyte <ctype.h> ANSI, Win 95, Win NT

For additional compatibility information, see Compatibility in the Introduction.


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

isleadbyte returns a nonzero value if the argument satisfies the test condition or 0 if it does not. In the “C” locale and in single-byte – character set (SBCS) locales, isleadbyte always returns 0.



Integer to test


The isleadbyte macro returns a nonzero value if its argument is the first byte of a multibyte character. isleadbyte produces a meaningful result for any integer argument from –1 (EOF) to UCHAR_MAX (0xFF), inclusive. The result of the test depends upon the LC_CTYPE category setting of the current locale; see setlocale for more information.

The expected argument type of isleadbyte is int; if a signed character is passed, the compiler may convert it to an integer by sign extension, yielding unpredictable results.

Generic-Text Routine Mappings

TCHAR.H Routine _UNICODE & _MBCS Not Defined _MBCS Defined _UNICODE Defined
_istleadbyte Always returns false _isleadbyte Always returns false

Byte Classification Routines, Locale Routines

See Also   _ismbb Routine Overview