.\"	$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 April 15, 1994
.Dt MUNMAP 2
.Os
.Sh NAME
.Nm munmap
.Nd remove a mapping
.Sh SYNOPSIS
.Fd #include <sys/mman.h>
.Ft int
.Fo munmap
.Fa "void *addr"
.Fa "size_t len"
.Fc
.Sh DESCRIPTION
The
.Fn munmap
system call
deletes the mappings for the specified address range,
causing 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 (i.e., a multiple of the page size).
.\" ===========
.It Bq Er EINVAL
The
.Fa len
parameter was negative or zero.
.\" ===========
.It Bq Er EINVAL
Some part of the region being unmapped is not part of the currently
valid address space.
.El
.Sh LEGACY SYNOPSIS
.Fd #include <sys/types.h>
.Fd #include <sys/mman.h>
.Pp
The include file
.In sys/types.h
is necessary.
.Pp
.Ft int
.br
.Fo munmap
.Fa "caddr_t addr"
.Fa "size_t len"
.Fc ;
.Pp
The type of
.Fa addr
has changed.
.Sh "SEE ALSO"
.Xr getpagesize 3 ,
.Xr msync 2 ,
.Xr munmap 2 ,
.Xr mprotect 2 ,
.Xr madvise 2 ,
.Xr mincore 2 ,
.Xr compat 5
.Sh HISTORY
The
.Fn munmap
function first appeared in 4.4BSD.