1 .\" Copyright (C) 1996 Andries Brouwer (aeb@cwi.nl)
3 .\" %%%LICENSE_START(VERBATIM)
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25 .TH MSYNC 2 2008-04-22 "Linux" "Linux Programmer's Manual"
27 msync \- synchronize a file with a memory map
29 .B #include <sys/mman.h>
31 .BI "int msync(void *" addr ", size_t " length ", int " flags );
34 flushes changes made to the in-core copy of a file that was mapped
38 Without use of this call
39 there is no guarantee that changes are written back before
42 To be more precise, the part of the file that
43 corresponds to the memory area starting at
51 argument may have the bits
61 specifies that an update be scheduled, but the call
64 asks for an update and waits for it to complete.
66 asks to invalidate other mappings of the same file
67 (so that they can be updated with the fresh values just written).
69 On success, zero is returned.
70 On error, \-1 is returned, and
79 and a memory lock exists for the specified address range.
83 is not a multiple of PAGESIZE; or any bit other than
84 .BR MS_ASYNC " | " MS_INVALIDATE " | " MS_SYNC
95 The indicated memory (or part of it) was not mapped.
99 This call was introduced in Linux 1.3.21, and then used
103 In Linux 2.4.19 this was changed to the POSIX value
106 On POSIX systems on which
109 .B _POSIX_MAPPED_FILES
111 .B _POSIX_SYNCHRONIZED_IO
114 to a value greater than 0.
117 .\" POSIX.1-2001: It shall be defined to -1 or 0 or 200112L.
118 .\" -1: unavailable, 0: ask using sysconf().
119 .\" glibc defines them to 1.
123 B.O. Gallmeister, POSIX.4, O'Reilly, pp. 128-129 and 389-391.
125 This page is part of release 3.64 of the Linux
128 A description of the project,
129 and information about reporting bugs,
131 \%http://www.kernel.org/doc/man\-pages/.