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. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. 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.\" @(#)index.3 8.1 (Berkeley) 6/4/93 35.\" $FreeBSD: src/lib/libc/string/index.3,v 1.3.2.3 2001/12/14 18:33:59 ru Exp $ 36.\" $DragonFly: src/lib/libc/string/index.3,v 1.2 2003/06/17 04:26:46 dillon Exp $ 37.\" 38.Dd June 4, 1993 39.Dt INDEX 3 40.Os 41.Sh NAME 42.Nm index 43.Nd locate character in string 44.Sh LIBRARY 45.Lb libc 46.Sh SYNOPSIS 47.In string.h 48.Ft char * 49.Fn index "const char *s" "int c" 50.Sh DESCRIPTION 51The 52.Fn index 53function 54locates the first character matching 55.Fa c 56(converted to a 57.Em char ) 58in the null-terminated string 59.Fa s . 60.Sh RETURN VALUES 61A pointer to the character is returned if it is found; otherwise 62.Dv NULL 63is returned. 64If 65.Fa c 66is '\e0', 67.Fn index 68locates the terminating '\e0'. 69.Sh SEE ALSO 70.Xr memchr 3 , 71.Xr rindex 3 , 72.Xr strchr 3 , 73.Xr strcspn 3 , 74.Xr strpbrk 3 , 75.Xr strrchr 3 , 76.Xr strsep 3 , 77.Xr strspn 3 , 78.Xr strstr 3 , 79.Xr strtok 3 80.Sh HISTORY 81A 82.Fn index 83function appeared in 84.At v6 . 85