1.\" $OpenBSD: munmap.2,v 1.21 2024/01/21 17:00:42 deraadt 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: January 21 2024 $ 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.It Bq Er EPERM 66The 67.Fa addr 68and 69.Fa len 70parameters 71specify a region which contains at least one page marked immutable. 72.El 73.Sh SEE ALSO 74.Xr madvise 2 , 75.Xr mimmutable 2 , 76.Xr mlock 2 , 77.Xr mlockall 2 , 78.Xr mmap 2 , 79.Xr mprotect 2 , 80.Xr msync 2 , 81.Xr getpagesize 3 82.Sh STANDARDS 83When 84.Fa len 85is non-zero, the 86.Fn munmap 87function conforms to 88.St -p1003.1-2008 . 89.Sh HISTORY 90The 91.Fn munmap 92system call has been available since 93.Bx 4.3 Net/2 . 94.Sh CAVEATS 95.St -p1003.1-2008 96specifies that 97.Fn munmap 98shall fail with 99.Er EINVAL 100if 101.Fa len 102is 0. 103.Ox 104performs no action in this case. 105