|| Linux Programmer's Manual
NAME msync - synchronize a file with a memory map
int msync(void *
() flushes changes made to the in-core copy of a file that was mapped into memory using
(2) back to disk. Without use of this call there is no guarantee that changes are written back before
(2) is called. To be more precise, the part of the file that corresponds to the memory area starting at
and having length
argument may have the bits
set, but not both
specifies that an update be scheduled, but the call returns immediately.
asks for an update and waits for it to complete.
asks to invalidate other mappings of the same file (so that they can be updated with the fresh values just written).
RETURN VALUE On success, zero is returned. On error, -1 is returned, and
errno is set appropriately.
MS_INVALIDATE was specified in
flags, and a memory lock exists for the specified address range.
addr is not a multiple of PAGESIZE; or any bit other than
MS_SYNC is set in
flags; or both
MS_ASYNC are set in
The indicated memory (or part of it) was not mapped.
This call was introduced in Linux 1.3.21, and then used
. In Linux 2.4.19 this was changed to the POSIX value
AVAILABILITY On POSIX systems on which
msync() is available, both
_POSIX_SYNCHRONIZED_IO are defined in
<unistd.h> to a value greater than 0. (See also
B.O. Gallmeister, POSIX.4, O'Reilly, pp. 128-129 and 389-391.
COLOPHON This page is part of release 3.53 of the Linux
man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.