.\"	$NetBSD: memmem.3,v 1.1 2005/03/13 14:47:02 perry Exp $
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.\" Copyright (c) 2005 The NetBSD Foundation, Inc.
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.\" This code is derived from software contributed to The NetBSD Foundation
.\" by Perry E. Metzger of Metzger, Dowdeswell & Co. LLC.
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.Dd March 12, 2005
.Dt MEMMEM 3
.Os
.Sh NAME
.Nm memmem
.Nd locate substring in byte string
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In string.h
.Ft void *
.Fn memmem "const void *block" "size_t blen" "const void *pat" "size_t plen"
.Sh DESCRIPTION
The
.Fn memmem
function locates the first occurrence of the binary string
.Fa pat
of size
.Fa plen
bytes in within the byte string
.Fa block
of size
.Fa blen
bytes.
.Sh RETURN VALUES
The
.Fn memmem
function returns a pointer to the substring located, or
.Dv NULL
if no such substring exists within
.Fa block .
.Pp
If
.Fa plen
is zero,
.Fa block
is returned, i.e. a zero length
.Fa pat
is deemed to match the start of the string, as with
.Xr strstr 3 .
.Sh SEE ALSO
.Xr bm 3 ,
.Xr memchr 3 ,
.Xr strchr 3 ,
.Xr strstr 3
.Sh STANDARDS
The
.Fn memmem
function is not currently standardized.
However, it is meant to be API compatible with functions in
.Fx
and Linux.
.Sh HISTORY
.Fn memmem
first appeared in the Free Software Foundation's glibc library.