freebsd-nq/lib/libc/locale/isxdigit.3

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.\"     @(#)isxdigit.3	8.1 (Berkeley) 6/4/93
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.Dd August 21, 2004
.Dt ISXDIGIT 3
.Os
.Sh NAME
.Nm isxdigit, ishexnumber
.Nd hexadecimal-digit character test
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In ctype.h
.Ft int
.Fn isxdigit "int c"
.Ft int
.Fn ishexnumber "int c"
.Sh DESCRIPTION
The
.Fn isxdigit
function tests for any hexadecimal-digit character.
Regardless of locale, this includes the following characters only:
.Pp
.Bl -column \&``0''______ \&``0''______ \&``0''______ \&``0''______ \&``0''______
.It "\&``0''\t``1''\t``2''\t``3''\t``4''"
.It "\&``5''\t``6''\t``7''\t``8''\t``9''"
.It "\&``A''\t``B''\t``C''\t``D''\t``E''"
.It "\&``F''\t``a''\t``b''\t``c''\t``d''"
.It "\&``e''\t``f''"
.El
.Pp
The
.Fn ishexnumber
function behaves similarly to
.Fn isxdigit ,
but may recognize additional characters,
depending on the current locale setting.
.Pp
For single C
.Va char Ns s
locales (see
.Xr multibyte 3 )
the value of the argument is
representable as an
.Li unsigned char
or the value of
.Dv EOF .
.Sh RETURN VALUES
The
.Fn isxdigit
function returns zero if the character tests false and
returns non-zero if the character tests true.
.Sh COMPATIBILITY
The
.Bx 4.4
extension of accepting arguments outside of the range of the
.Vt "unsigned char"
type in locales with large character sets is considered obsolete
and may not be supported in future releases.
The
.Fn iswxdigit
function should be used instead.
.Sh SEE ALSO
.Xr ctype 3 ,
.Xr iswxdigit 3 ,
.Xr multibyte 3 ,
.Xr ascii 7
.Sh STANDARDS
The
.Fn isxdigit
function conforms to
.St -isoC .
.Sh HISTORY
The
.Fn ishexnumber
function appeared in
.Bx 4.4 .