3.12 isxdigit, isxdigit_l—hexadecimal digit predicate

Synopsis

#include <ctype.h>
int isxdigit(int c);

#include <ctype.h>
int isxdigit_l(int c, locale_t locale);

Description
isxdigit is a macro which classifies singlebyte charset values by table lookup. It is a predicate returning non-zero for hexadecimal digits, and 0 for other characters. It is defined only if c is representable as an unsigned char or if c is EOF.

isxdigit_l is like isxdigit but performs the check based on the locale specified by the locale object locale. If locale is LC_GLOBAL_LOCALE or not a valid locale object, the behaviour is undefined.

You can use a compiled subroutine instead of the macro definition by undefining the macro using ‘#undef isxdigit’ or ‘#undef isxdigit_l’.

Returns
isxdigit, isxdigit_l return non-zero if c is a hexadecimal digit (0–9, a–f, or A–F).

Portability
isxdigit is ANSI C. isxdigit_l is POSIX-1.2008.

No supporting OS subroutines are required.