1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.roff% 5.\" 6.\" @(#)madvise.2 8.1 (Berkeley) 06/09/93 7.\" 8.Dd 9.Dt MADVISE 2 10.Os 11.Sh NAME 12.Nm madvise 13.Nd give advise about use of memory 14.Sh SYNOPSIS 15.Fn madvise "caddr_t addr" "int len" "int behav" 16.Sh DESCRIPTION 17The 18.Fn madvise 19system call 20allows a process that has knowledge of its memory behavior 21to describe it to the system. 22The known behaviors are given in 23.Pa <sys/mman.h> : 24.Bd -literal 25#define MADV_NORMAL 0 /* no further special treatment */ 26#define MADV_RANDOM 1 /* expect random page references */ 27#define MADV_SEQUENTIAL 2 /* expect sequential references */ 28#define MADV_WILLNEED 3 /* will need these pages */ 29#define MADV_DONTNEED 4 /* don't need these pages */ 30#define MADV_SPACEAVAIL 5 /* insure that resources are reserved */ 31.Ed 32.Sh SEE ALSO 33.Xr msync 2 , 34.Xr munmap 2 , 35.Xr mprotect 2 , 36.Xr mincore 2 37.Sh HISTORY 38The 39.Nm madvise 40function first appeared in 4.4BSD. 41