1.\" $OpenBSD: munmap.2,v 1.19 2019/12/21 05:23:38 jsg Exp $ 2.\" $NetBSD: munmap.2,v 1.5 1995/02/27 12:35:03 cgd Exp $ 3.\" 4.\" Copyright (c) 1991, 1993 5.\" The Regents of the University of California. All rights reserved. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" @(#)munmap.2 8.2 (Berkeley) 4/15/94 32.\" 33.Dd $Mdocdate: December 21 2019 $ 34.Dt MUNMAP 2 35.Os 36.Sh NAME 37.Nm munmap 38.Nd remove a mapping 39.Sh SYNOPSIS 40.In sys/mman.h 41.Ft int 42.Fn munmap "void *addr" "size_t len" 43.Sh DESCRIPTION 44The 45.Fn munmap 46system call 47deletes the mappings for the specified address range, 48and causes further references to addresses within the range 49to generate invalid memory references. 50.Sh RETURN VALUES 51.Rv -std 52.Sh ERRORS 53.Fn munmap 54will fail if: 55.Bl -tag -width Er 56.It Bq Er EINVAL 57The 58.Fa addr 59and 60.Fa len 61parameters 62specify a region that would extend beyond the end of the address space, 63or some part of the region being unmapped is not part of the currently 64valid address space. 65.El 66.Sh SEE ALSO 67.Xr madvise 2 , 68.Xr mlock 2 , 69.Xr mlockall 2 , 70.Xr mmap 2 , 71.Xr mprotect 2 , 72.Xr msync 2 , 73.Xr getpagesize 3 74.Sh STANDARDS 75When 76.Fa len 77is non-zero, the 78.Fn munmap 79function conforms to 80.St -p1003.1-2008 . 81.Sh HISTORY 82The 83.Fn munmap 84system call has been available since 85.Bx 4.3 Net/2 . 86.Sh CAVEATS 87.St -p1003.1-2008 88specifies that 89.Fn munmap 90shall fail with 91.Er EINVAL 92if 93.Fa len 94is 0. 95.Ox 96performs no action in this case. 97