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.\" Copyright (c) 2001 Mike Barcroft <mike@FreeBSD.org>
.\" Copyright (c) 1990, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" Chris Torek and the American National Standards Committee X3,
.\" on Information Processing Systems.
.\"
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.\" modification, are permitted provided that the following conditions
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.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" 3. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\"     @(#)strstr.3	8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
.Dd October 11, 2001
37
.Dt STRSTR 3bsd
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.Os
.Sh NAME
.Nm strnstr
.Nd locate a substring in a string
.Sh LIBRARY
.ds str-Lb-libbsd Utility functions from BSD systems (libbsd, \-lbsd)
.Lb libbsd
.Sh SYNOPSIS
46 47 48 49
.In string.h
(See
.Xr libbsd 7
for include usage.)
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.Ft char *
.Fn strnstr "const char *big" "const char *little" "size_t len"
.Sh DESCRIPTION
The
.Fn strnstr
function
locates the first occurrence of the null-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
.Fx
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
.Dv NULL ,
because only the first 4 characters of
.Va largestring
are searched:
.Bd -literal -offset indent
const char *largestring = "Foo Bar Baz";
const char *smallstring = "Bar";
char *ptr;

ptr = strnstr(largestring, smallstring, 4);
.Ed
.Sh SEE ALSO
.Xr strstr 3 ,
.Xr strcasestr 3 ,
.Xr memchr 3 ,
.Xr memmem 3 ,
.Xr strchr 3 ,
.Xr strcspn 3 ,
.Xr strpbrk 3 ,
.Xr strrchr 3 ,
.Xr strsep 3 ,
.Xr strspn 3 ,
.Xr strtok 3 ,
.Xr wcsstr 3