1.\" Copyright (c) 2001 Mike Barcroft <mike@FreeBSD.org> 2.\" Copyright (c) 1990, 1991, 1993 3.\" The Regents of the University of California. All rights reserved. 4.\" 5.\" This code is derived from software contributed to Berkeley by 6.\" Chris Torek and the American National Standards Committee X3, 7.\" on Information Processing Systems. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. Neither the name of the University nor the names of its contributors 18.\" may be used to endorse or promote products derived from this software 19.\" without specific prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 22.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 25.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31.\" SUCH DAMAGE. 32.\" 33.\" from: @(#)strstr.3 8.1 (Berkeley) 6/4/93 34.\" $NetBSD: strstr.3,v 1.10 2006/10/16 08:48:45 wiz Exp $ 35.\" 36.Dd July 3, 2004 37.Dt STRSTR 3 38.Os 39.Sh NAME 40.Nm strstr , strcasestr 41.Nd locate a substring in a string 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In string.h 46.Ft char * 47.Fn strstr "const char *big" "const char *little" 48.Ft char * 49.Fn strcasestr "const char *big" "const char *little" 50.Sh DESCRIPTION 51The 52.Fn strstr 53function 54locates the first occurrence of the nul-terminated string 55.Fa little 56in the nul-terminated string 57.Fa big . 58.Pp 59The 60.Fn strcasestr 61function is similar to 62.Fn strstr , 63but ignores the case of both strings. 64.Sh RETURN VALUES 65If 66.Fa little 67is an empty string, 68.Fa big 69is returned; 70if 71.Fa little 72occurs nowhere in 73.Fa big , 74.Dv NULL 75is returned; 76otherwise a pointer to the first character of the first occurrence of 77.Fa little 78is returned. 79.Sh EXAMPLES 80The following sets the pointer 81.Va ptr 82to the 83.Qq Li Bar Baz 84portion of 85.Va largestring : 86.Bd -literal -offset indent 87const char *largestring = "Foo Bar Baz"; 88const char *smallstring = "Bar"; 89char *ptr; 90 91ptr = strstr(largestring, smallstring); 92.Ed 93.Sh SEE ALSO 94.Xr index 3 , 95.Xr memchr 3 , 96.Xr rindex 3 , 97.Xr strchr 3 , 98.Xr strcspn 3 , 99.Xr strpbrk 3 , 100.Xr strrchr 3 , 101.Xr strsep 3 , 102.Xr strspn 3 , 103.Xr strtok 3 104.Sh STANDARDS 105The 106.Fn strstr 107function 108conforms to 109.St -isoC . 110