freebsd-skq/lib/libc/locale/isdigit.3
2000-12-29 14:08:20 +00:00

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.\" Copyright (c) 1991, 1993
.\" The Regents of the University of California. All rights reserved.
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.\" the American National Standards Committee X3, on Information
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.\" @(#)isdigit.3 8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd June 4, 1993
.Dt ISDIGIT 3
.Os
.Sh NAME
.Nm isdigit
.Nd decimal-digit character test
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.Fd #include <ctype.h>
.Ft int
.Fn isdigit "int c"
.Sh DESCRIPTION
The
.Fn isdigit
function tests for any decimal-digit character.
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 .
In the ASCII character set, this includes the following characters
(with their numeric values shown in octal):
.Pp
.Bl -column \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__ \&000_``0''__
.It "\&060\ ``0'' \t061\ ``1'' \t062\ ``2'' \t063\ ``3'' \t064\ ``4''"
.It "\&065\ ``5'' \t066\ ``6'' \t067\ ``7'' \t070\ ``8'' \t071\ ``9''"
.El
.Sh RETURN VALUES
The
.Fn isdigit
function returns zero if the character tests false and
returns non-zero if the character tests true.
.Sh SEE ALSO
.Xr ctype 3 ,
.Xr multibyte 3 ,
.Xr ascii 7
.Sh STANDARDS
The
.Fn isdigit
function conforms to
.St -ansiC .