newlib/libc/ctype/isxdigit.c

   1 /*
   2 FUNCTION
   3         <<isxdigit>>, <<isxdigit_l>>---hexadecimal digit predicate
   4
   5 INDEX
   6         isxdigit
   7
   8 INDEX
   9         isxdigit_l
  10
  11 SYNOPSIS
  12         #include <ctype.h>
  13         int isxdigit(int <[c]>);
  14
  15         #include <ctype.h>
  16         int isxdigit_l(int <[c]>, locale_t <[locale]>);
  17
  18 DESCRIPTION
  19 <<isxdigit>> is a macro which classifies singlebyte charset values by table
  20 lookup.  It is a predicate returning non-zero for hexadecimal digits,
  21 and <<0>> for other characters.  It is defined only if <[c]> is
  22 representable as an unsigned char or if <[c]> is EOF.
  23
  24 <<isxdigit_l>> is like <<isxdigit>> but performs the check based on the
  25 locale specified by the locale object locale.  If <[locale]> is
  26 LC_GLOBAL_LOCALE or not a valid locale object, the behaviour is undefined.
  27
  28 You can use a compiled subroutine instead of the macro definition by
  29 undefining the macro using `<<#undef isxdigit>>' or `<<#undef isxdigit_l>>'.
  30
  31 RETURNS
  32 <<isxdigit>>, <<isxdigit_l>> return non-zero if <[c]> is a hexadecimal digit
  33 (<<0>>--<<9>>, <<a>>--<<f>>, or <<A>>--<<F>>).
  34
  35 PORTABILITY
  36 <<isxdigit>> is ANSI C.
  37 <<isxdigit_l>> is POSIX-1.2008.
  38
  39 No supporting OS subroutines are required.
  40 */
  41 #include <_ansi.h>
  42 #include <ctype.h>
  43
  44
  45 #undef isxdigit
  46 int
  47 isxdigit (int c)
  48 {
  49         return(__CTYPE_PTR[c+1] & ((_X)|(_N)));
  50 }