xref: /minix3/lib/libc/string/strstr.3 (revision 0a6a1f1d05b60e214de2f05a7310ddd1f0e590e7)

.\" Copyright (c) 2001 Mike Barcroft <mike@FreeBSD.org>
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.\"     from: @(#)strstr.3	8.1 (Berkeley) 6/4/93
.\"	$NetBSD: strstr.3,v 1.12 2014/09/24 18:43:21 wiz Exp $
.\"
.Dd September 24, 2014
.Dt STRSTR 3
.Os
.Sh NAME
.Nm strstr , strcasestr , strnstr
.Nd locate a substring in a string
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In string.h
.Ft char *
.Fn strstr "const char *big" "const char *little"
.Ft char *
.Fn strcasestr "const char *big" "const char *little"
.Ft char *
.Fn strnstr "const char *big" "const char *little" "size_t len"
.Sh DESCRIPTION
The
.Fn strstr
function
locates the first occurrence of the nul-terminated string
.Fa little
in the nul-terminated string
.Fa big .
.Pp
The
.Fn strcasestr
function is similar to
.Fn strstr ,
but ignores the case of both strings.
The
.Fn strnstr
function
locates the first occurrence of the NUL-terminated string
.Fa little
in the string
.Fa big ,
where not more than
.Fa len
characters are searched.
Characters that appear after a
.Ql \e0
character are not searched.
Since the
.Fn strnstr
function is a
.Nx
specific API, it should only be used when portability is not a concern.
.Sh RETURN VALUES
If
.Fa little
is an empty string,
.Fa big
is returned;
if
.Fa little
occurs nowhere in
.Fa big ,
.Dv NULL
is returned;
otherwise a pointer to the first character of the first occurrence of
.Fa little
is returned.
.Sh EXAMPLES
The following sets the pointer
.Va ptr
to the
.Qq Li Bar Baz
portion of
.Va largestring :
.Bd -literal -offset indent
const char *largestring = "Foo Bar Baz";
const char *smallstring = "Bar";
char *ptr;

ptr = strstr(largestring, smallstring);
.Ed
.Sh SEE ALSO
.Xr index 3 ,
.Xr memchr 3 ,
.Xr rindex 3 ,
.Xr strchr 3 ,
.Xr strcspn 3 ,
.Xr strpbrk 3 ,
.Xr strrchr 3 ,
.Xr strsep 3 ,
.Xr strspn 3 ,
.Xr strtok 3
.Sh STANDARDS
The
.Fn strstr
function
conforms to
.St -isoC .
.Sh HISTORY
The
.Fn strnstr
function originated in
.Fx .