ISXDIGIT(3) Library Functions Manual ISXDIGIT(3)

isxdigit, ishexnumber — hexadecimal-digit character test

Standard C Library (libc, -lc)

#include <ctype.h>

int
isxdigit(int c);

int
ishexnumber(int c);

The () 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 () 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.

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

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.

ctype(3), isalnum_l(3), iswxdigit(3), ascii(7)

The isxdigit() function conforms to ISO/IEC 9899:1990 (“ISO C90”).

The ishexnumber() function appeared in 4.4BSD.

July 17, 2005 macOS 15.0