freebsd man page for ishexnumber

ISXDIGIT(3)						   BSD Library Functions Manual 					       ISXDIGIT(3)

NAME
     isxdigit, ishexnumber -- hexadecimal-digit character test

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <ctype.h>

     int
     isxdigit(int c);

     int
     ishexnumber(int c);

DESCRIPTION
     The isxdigit() function tests for any hexadecimal-digit character.  Regardless of locale, this includes the following characters only:

     ``0''	   ``1''	 ``2''	       ``3''	     ``4''
     ``5''	   ``6''	 ``7''	       ``8''	     ``9''
     ``A''	   ``B''	 ``C''	       ``D''	     ``E''
     ``F''	   ``a''	 ``b''	       ``c''	     ``d''
     ``e''	   ``f''

     The ishexnumber() function behaves similarly to isxdigit(), but may recognize additional characters, depending on the current locale setting.

     The value of the argument must be representable as an unsigned char or the value of EOF.

RETURN VALUES
     The isxdigit() function returns zero if the character tests false and returns non-zero if the character tests true.

COMPATIBILITY
     The 4.4BSD extension of accepting arguments outside of the range of the unsigned char type in locales with large character sets is considered
     obsolete and may not be supported in future releases.  The iswxdigit() function should be used instead.

SEE ALSO
     ctype(3), iswxdigit(3), ascii(7)

STANDARDS
     The isxdigit() function conforms to ISO/IEC 9899:1990 (``ISO C90'').

HISTORY
     The ishexnumber() function appeared in 4.4BSD.

BSD
								   July 17, 2005							       BSD