.\"	$OpenBSD: munmap.2,v 1.14 2009/01/31 16:52:15 pyr Exp $
.\"	$NetBSD: munmap.2,v 1.5 1995/02/27 12:35:03 cgd Exp $
.\"
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.\"	@(#)munmap.2	8.2 (Berkeley) 4/15/94
.\"
.Dd $Mdocdate: January 31 2009 $
.Dt MUNMAP 2
.Os
.Sh NAME
.Nm munmap
.Nd remove a mapping
.Sh SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <sys/mman.h>
.Ft int
.Fn munmap "void *addr" "size_t len"
.Sh DESCRIPTION
The
.Fn munmap
system call
deletes the mappings for the specified address range,
and causes further references to addresses within the range
to generate invalid memory references.
.Sh RETURN VALUES
Upon successful completion,
.Nm munmap
returns zero.
Otherwise, a value of \-1 is returned and
.Va errno
is set to indicate the error.
.Sh ERRORS
.Fn munmap
will fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The
.Fa addr
parameter was not page aligned,
.Fa addr
and
.Fa len
specify a region that would extend beyond the end of the address space,
or some part of the region being unmapped is not part of the currently
valid address space.
.El
.Sh SEE ALSO
.Xr madvise 2 ,
.Xr mincore 2 ,
.Xr mlock 2 ,
.Xr mlockall 2 ,
.Xr mmap 2 ,
.Xr mprotect 2 ,
.Xr msync 2 ,
.Xr getpagesize 3
.Sh HISTORY
The
.Fn munmap
function first appeared in
.Bx 4.4 .