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3.12 isxdigit—hexadecimal digit predicate

Synopsis

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

Description
isxdigit is a macro which classifies ASCII integer 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.

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


Returns
isxdigit returns non-zero if c is a hexadecimal digit (09, af, or AF).


Portability
isxdigit is ANSI C.

No supporting OS subroutines are required.