117 lines
3.3 KiB
Groff
117 lines
3.3 KiB
Groff
.\" $OpenBSD: isdigit.3,v 1.14 2023/01/20 17:21:12 millert Exp $
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.\"
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.\" Copyright (c) 1991 The Regents of the University of California.
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.\" Copyright (c) 2017 Ingo Schwarze <schwarze@openbsd.org>
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" the American National Standards Committee X3, on Information
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.\" Processing Systems.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.Dd $Mdocdate: January 20 2023 $
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.Dt ISDIGIT 3
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.Os
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.Sh NAME
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.Nm isdigit ,
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.Nm isdigit_l
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.Nd decimal-digit single-byte character test
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.Sh SYNOPSIS
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.In ctype.h
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.Ft int
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.Fn isdigit "int c"
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.Ft int
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.Fn isdigit_l "int c" "locale_t locale"
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.Sh DESCRIPTION
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The
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.Fn isdigit
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and
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.Fn isdigit_l
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functions test for any decimal-digit character.
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In the C locale, the complete list of decimal digits is 0 and 1\(en9.
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.Ox
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always uses the C locale for these functions,
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ignoring the global locale, the thread-specific locale, and the
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.Fa locale
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argument.
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.Sh RETURN VALUES
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These functions return zero if the character tests false or
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non-zero if the character tests true.
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.Sh ENVIRONMENT
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On systems supporting non-ASCII single-byte character encodings,
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different
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.Fa c
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arguments may correspond to the digits, and the results of
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.Fn isdigit
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may depend on the
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.Ev LC_CTYPE
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.Xr locale 1 .
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.Sh SEE ALSO
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.Xr isalnum 3 ,
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.Xr isalpha 3 ,
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.Xr isascii 3 ,
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.Xr isblank 3 ,
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.Xr iscntrl 3 ,
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.Xr isgraph 3 ,
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.Xr islower 3 ,
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.Xr isprint 3 ,
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.Xr ispunct 3 ,
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.Xr isspace 3 ,
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.Xr isupper 3 ,
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.Xr iswdigit 3 ,
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.Xr isxdigit 3 ,
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.Xr stdio 3 ,
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.Xr toascii 3 ,
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.Xr tolower 3 ,
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.Xr toupper 3 ,
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.Xr ascii 7
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.Sh STANDARDS
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The
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.Fn isdigit
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function conforms to
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.St -ansiC ,
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and
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.Fn isdigit_l
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to
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.St -p1003.1-2008 .
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.Sh HISTORY
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The
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.Fn isdigit
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function first appeared in
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.At v7 ,
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and
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.Fn isdigit_l
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has been available since
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.Ox 6.2 .
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.Sh CAVEATS
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The argument
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.Fa c
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must be
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.Dv EOF
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or representable as an
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.Vt unsigned char ;
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otherwise, the result is undefined.
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