81 lines
2.9 KiB
Groff
81 lines
2.9 KiB
Groff
.\" $NetBSD: madvise.2,v 1.20 2003/08/07 16:44:01 agc 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
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" 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
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 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
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)madvise.2 8.1 (Berkeley) 6/9/93
|
|
.\"
|
|
.Dd August 11, 2002
|
|
.Dt MADVISE 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm madvise
|
|
.Nd give advice about use of memory
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In 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 \*[Lt]sys/mman.h\*[Gt] :
|
|
.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 /* ensure that resources are reserved */
|
|
#define MADV_FREE 6 /* pages are empty, free them */
|
|
.Ed
|
|
.Sh RETURN VALUES
|
|
Upon successful completion,
|
|
a value of 0 is returned.
|
|
Otherwise, a value of -1 is returned and
|
|
.Va errno
|
|
is set to indicate the error.
|
|
.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.
|