1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Chris Torek. 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" from: @(#)index.3 8.1 (Berkeley) 6/4/93 31.\" $NetBSD: index.3,v 1.13 2010/04/29 06:54:26 jruoho Exp $ 32.\" 33.Dd April 29, 2010 34.Dt INDEX 3 35.Os 36.Sh NAME 37.Nm index 38.Nd locate character in string 39.Sh LIBRARY 40.Lb libc 41.Sh SYNOPSIS 42.In strings.h 43.Ft char * 44.Fn index "const char *s" "int c" 45.Sh DESCRIPTION 46The 47.Fn index 48function 49locates the first character matching 50.Fa c 51(converted to a 52.Em char ) 53in the nul-terminated string 54.Fa s . 55.Sh RETURN VALUES 56A pointer to the character is returned if it is found; otherwise 57.Dv NULL 58is returned. 59If 60.Fa c 61is '\e0', 62.Fn index 63locates the terminating '\e0'. 64.Sh SEE ALSO 65.Xr memchr 3 , 66.Xr rindex 3 , 67.Xr strchr 3 , 68.Xr strcspn 3 , 69.Xr strpbrk 3 , 70.Xr strrchr 3 , 71.Xr strsep 3 , 72.Xr strspn 3 , 73.Xr strstr 3 , 74.Xr strtok 3 75.Sh STANDARDS 76The 77.Fn index 78function conforms to 79.St -p1003.1-2001 . 80The 81.St -p1003.1-2004 82revision marked it as legacy and recommended the use of 83.Xr strchr 3 84instead. 85The 86.St -p1003.1-2008 87revision removed 88.Fn index 89from the specification. 90.Sh HISTORY 91An 92.Fn index 93function appeared in 94.At v6 . 95