1.\"	$OpenBSD: mprotect.2,v 1.10 2004/04/15 19:52:18 jmc Exp $
2.\"	$NetBSD: mprotect.2,v 1.6 1995/10/12 15:41:08 jtc Exp $
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31.\"	@(#)mprotect.2	8.1 (Berkeley) 6/9/93
32.\"
33.Dd June 9, 1993
34.Dt MPROTECT 2
35.Os
36.Sh NAME
37.Nm mprotect
38.Nd control the protection of pages
39.Sh SYNOPSIS
40.Fd #include <sys/types.h>
41.Fd #include <sys/mman.h>
42.Ft int
43.Fn mprotect "void *addr" "size_t len" "int prot"
44.Sh DESCRIPTION
45The
46.Fn mprotect
47system call
48changes the specified pages to have protection
49.Fa prot .
50Not all implementations will guarantee protection on a page basis;
51the granularity of protection changes may be as large as an entire region.
52.Pp
53The protections (region accessibility) are specified in the
54.Fa prot
55argument by
56.Tn OR Ns 'ing
57the following values:
58.Bl -tag -width MAP_FIXEDX
59.It Dv PROT_EXEC
60Pages may be executed.
61.It Dv PROT_READ
62Pages may be read.
63.It Dv PROT_WRITE
64Pages may be written.
65.It Dv PROT_NONE
66No permissions.
67.El
68.Sh RETURN VALUES
69Upon successful completion,
70a value of 0 is returned.
71Otherwise, a value of \-1 is returned and
72.Va errno
73is set to indicate the error.
74.Sh SEE ALSO
75.Xr madvise 2 ,
76.Xr mincore 2 ,
77.Xr msync 2 ,
78.Xr munmap 2
79.Sh HISTORY
80The
81.Fn mprotect
82function first appeared in
83.Bx 4.4 .
84