NetBSD/lib/libc/sys/madvise.2
kleink 15be242b3a Add a LIBRARY section to system call manual pages. While it's clear that the
libraries contain stubs only (with minor exceptions a la pipe(2)), the purpose
of this section is to provide linkage information.
1999-12-02 21:42:35 +00:00

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.\" $NetBSD: madvise.2,v 1.12 1999/12/02 21:42:37 kleink Exp $
.\"
.\" Copyright (c) 1991, 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
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.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
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.\" 3. All advertising materials mentioning features or use of this software
.\" must display the following acknowledgement:
.\" This product includes software developed by the University of
.\" California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\" may be used to endorse or promote products derived from this software
.\" without specific prior written permission.
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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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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.\" SUCH DAMAGE.
.\"
.\" @(#)madvise.2 8.1 (Berkeley) 6/9/93
.\"
.Dd June 9, 1993
.Dt MADVISE 2
.Os
.Sh NAME
.Nm madvise
.Nd give advice about use of memory
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <sys/mman.h>
.Ft int
.Fn madvise "void *addr" "size_t len" "int behav"
.Sh DESCRIPTION
The
.Fn madvise
system call
allows a process that has knowledge of its memory behavior
to describe it to the system.
The known behaviors are given in
.Pa <sys/mman.h> :
.Bd -literal
#define MADV_NORMAL 0 /* no further special treatment */
#define MADV_RANDOM 1 /* expect random page references */
#define MADV_SEQUENTIAL 2 /* expect sequential references */
#define MADV_WILLNEED 3 /* will need these pages */
#define MADV_DONTNEED 4 /* don't need these pages */
#define MADV_SPACEAVAIL 5 /* insure that resources are reserved */
#define MADV_FREE 6 /* pages are empty, free them */
.Ed
.Sh SEE ALSO
.Xr mincore 2 ,
.Xr mprotect 2 ,
.Xr msync 2 ,
.Xr munmap 2
.Sh HISTORY
The
.Nm madvise
system call first appeared in
.Bx 4.4 ,
but until
.Nx 1.5
it did not perform any of the requests on, or change any behavior of the
address range given.