1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)msync.2 8.1 (Berkeley) 6/9/93 33.\" 34.Dd June 9, 1993 35.Dt MSYNC 2 36.Os 37.Sh NAME 38.Nm msync 39.Nd synchronize a mapped region 40.Sh SYNOPSIS 41.Fn msync "caddr_t addr" "int len" "int flags" 42.Sh DESCRIPTION 43The 44.Fn msync 45system call 46writes any modified pages back to the filesystem and updates 47the file modification time. 48If 49.Fa len 50is 0, all modified pages within the region containing 51.Fa addr 52will be flushed; 53if 54.Fa len 55is non-zero, only the pages containing 56.Fa addr 57and 58.Fa len 59succeeding locations will be examined. 60The 61.Fa flags 62argument may be specified as follows: 63.Bd -literal 64MS_ASYNC Return immediately (not currently implemented) 65MS_INVALIDATE Invalidate all cached data 66.Ed 67.Sh RETURN VALUES 68If any errors occur, -1 is returned and errno is set to indicate the 69error. Otherwise, a 0 value is returned. 70.Sh ERRORS 71.Fn msync 72will fail if: 73.Bl -tag -width Er 74.It Bq Er EINVAL 75.Fa addr 76is not a multiple of the hardware page size. 77.It Bq Er EINVAL 78.Fa len 79is too large or negative. 80.It Bq Er EINVAL 81.Fa flags 82was both MS_ASYNC and MS_INVALIDATE. Only one of these flags is allowed. 83.Sh SEE ALSO 84.Xr madvise 2 , 85.Xr munmap 2 , 86.Xr mprotect 2 , 87.Xr mincore 2 88.Sh HISTORY 89The 90.Fn msync 91function first appeared in 4.4BSD. 92