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.\" $FreeBSD$ 36.\" 37.Dd June 4, 1993 38.Dt INDEX 3 39.Os 40.Sh NAME 41.Nm index , rindex 42.Nd locate character in string 43.Sh LIBRARY 44.Lb libc 45.Sh SYNOPSIS 46.In strings.h 47.Ft "char *" 48.Fn index "const char *s" "int c" 49.Ft "char *" 50.Fn rindex "const char *s" "int c" 51.Sh DESCRIPTION 52The 53.Fn index 54function 55locates the first occurrence of 56.Fa c 57(converted to a 58.Vt char ) 59in the string pointed to by 60.Fa s . 61The terminating null character is considered part of the string; 62therefore if 63.Fa c 64is 65.Ql \e0 , 66the functions locate the terminating 67.Ql \e0 . 68.Pp 69The 70.Fn rindex 71function is identical to 72.Fn index , 73except it locates the last occurrence of 74.Fa c . 75.Sh RETURN VALUES 76The functions 77.Fn index 78and 79.Fn rindex 80return a pointer to the located character, or 81.Dv NULL 82if the character does not appear in the string. 83.Sh SEE ALSO 84.Xr memchr 3 , 85.Xr strchr 3 , 86.Xr strcspn 3 , 87.Xr strpbrk 3 , 88.Xr strrchr 3 , 89.Xr strsep 3 , 90.Xr strspn 3 , 91.Xr strstr 3 , 92.Xr strtok 3 93.Sh HISTORY 94The 95.Fn index 96and 97.Fn rindex 98functions appeared in 99.At v6 . 100Their prototypes existed previously in 101.In string.h 102before they were moved to 103.In strings.h 104for 105.St -p1003.1-2001 106compliance. 107