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.\" 32.Dd March 20, 2011 33.Dt INDEX 3 34.Os 35.Sh NAME 36.Nm index , rindex 37.Nd locate character in string 38.Sh LIBRARY 39.Lb libc 40.Sh SYNOPSIS 41.In strings.h 42.Ft "char *" 43.Fn index "const char *s" "int c" 44.Ft "char *" 45.Fn rindex "const char *s" "int c" 46.Sh DESCRIPTION 47.Bf -symbolic 48The 49.Fn index 50and 51.Fn rindex 52functions have been deprecated in favor of 53.Xr strchr 3 54and 55.Xr strrchr 3 . 56.Ef 57.Pp 58The 59.Fn index 60function 61locates the first occurrence of 62.Fa c 63(converted to a 64.Vt char ) 65in the string pointed to by 66.Fa s . 67The terminating null character is considered part of the string; 68therefore if 69.Fa c 70is 71.Ql \e0 , 72the functions locate the terminating 73.Ql \e0 . 74.Pp 75The 76.Fn rindex 77function is identical to 78.Fn index , 79except it locates the last occurrence of 80.Fa c . 81.Sh RETURN VALUES 82The functions 83.Fn index 84and 85.Fn rindex 86return a pointer to the located character, or 87.Dv NULL 88if the character does not appear in the string. 89.Sh SEE ALSO 90.Xr memchr 3 , 91.Xr strchr 3 , 92.Xr strcspn 3 , 93.Xr strpbrk 3 , 94.Xr strrchr 3 , 95.Xr strsep 3 , 96.Xr strspn 3 , 97.Xr strstr 3 , 98.Xr strtok 3 99.Sh HISTORY 100The 101.Fn index 102and 103.Fn rindex 104functions appeared in 105.At v6 . 106Their prototypes existed previously in 107.In string.h 108before they were moved to 109.In strings.h 110for 111.St -p1003.1-2001 112compliance. 113The functions are not specified by 114.St -p1003.1-2008 . 115