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.\" @(#)index.3 8.1 (Berkeley) 6/4/93 31.\" $FreeBSD$ 32.\" 33.Dd March 20, 2011 34.Dt INDEX 3 35.Os 36.Sh NAME 37.Nm index , rindex 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.Ft "char *" 46.Fn rindex "const char *s" "int c" 47.Sh DESCRIPTION 48.Bf -symbolic 49The 50.Fn index 51and 52.Fn rindex 53functions have been deprecated in favor of 54.Xr strchr 3 55and 56.Xr strrchr 3 . 57.Ef 58.Pp 59The 60.Fn index 61function 62locates the first occurrence of 63.Fa c 64(converted to a 65.Vt char ) 66in the string pointed to by 67.Fa s . 68The terminating null character is considered part of the string; 69therefore if 70.Fa c 71is 72.Ql \e0 , 73the functions locate the terminating 74.Ql \e0 . 75.Pp 76The 77.Fn rindex 78function is identical to 79.Fn index , 80except it locates the last occurrence of 81.Fa c . 82.Sh RETURN VALUES 83The functions 84.Fn index 85and 86.Fn rindex 87return a pointer to the located character, or 88.Dv NULL 89if the character does not appear in the string. 90.Sh SEE ALSO 91.Xr memchr 3 , 92.Xr strchr 3 , 93.Xr strcspn 3 , 94.Xr strpbrk 3 , 95.Xr strrchr 3 , 96.Xr strsep 3 , 97.Xr strspn 3 , 98.Xr strstr 3 , 99.Xr strtok 3 100.Sh HISTORY 101The 102.Fn index 103and 104.Fn rindex 105functions appeared in 106.At v6 . 107Their prototypes existed previously in 108.In string.h 109before they were moved to 110.In strings.h 111for 112.St -p1003.1-2001 113compliance. 114The functions are not specified by 115.St -p1003.1-2008 . 116