1.\" $NetBSD: isdigit.3,v 1.14 2008/04/17 16:25:36 apb Exp $ 2.\" 3.\" Copyright (c) 1991 The Regents of the University of California. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" the American National Standards Committee X3, on Information 8.\" Processing Systems. 9.\" 10.\" Redistribution and use in source and binary forms, with or without 11.\" modification, are permitted provided that the following conditions 12.\" are met: 13.\" 1. Redistributions of source code must retain the above copyright 14.\" notice, this list of conditions and the following disclaimer. 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in the 17.\" documentation and/or other materials provided with the distribution. 18.\" 3. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)isdigit.3 5.2 (Berkeley) 6/29/91 35.\" 36.Dd April 17, 2008 37.Dt ISDIGIT 3 38.Os 39.Sh NAME 40.Nm isdigit 41.Nd decimal-digit character test 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In ctype.h 46.Ft int 47.Fn isdigit "int c" 48.Sh DESCRIPTION 49The 50.Fn isdigit 51function tests for any decimal-digit character. 52.Sh RETURN VALUES 53The 54.Fn isdigit 55function returns zero if the character tests false and 56returns non-zero if the character tests true. 57.Sh SEE ALSO 58.Xr ctype 3 , 59.Xr isalnum 3 , 60.Xr isalpha 3 , 61.Xr isascii 3 , 62.Xr isblank 3 , 63.Xr iscntrl 3 , 64.Xr isgraph 3 , 65.Xr islower 3 , 66.Xr isprint 3 , 67.Xr ispunct 3 , 68.Xr isspace 3 , 69.Xr isupper 3 , 70.Xr isxdigit 3 , 71.Xr stdio 3 , 72.Xr toascii 3 , 73.Xr tolower 3 , 74.Xr toupper 3 , 75.Xr ascii 7 76.Sh STANDARDS 77The 78.Fn isdigit 79function conforms to 80.St -ansiC . 81.Sh CAVEATS 82The argument to 83.Fn isdigit 84must be 85.Dv EOF 86or representable as an 87.Vt unsigned char ; 88otherwise, the behavior is undefined. 89See the 90.Sx CAVEATS 91section of 92.Xr ctype 3 93for more details. 94