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MSYNC(2) System Calls Manual MSYNC(2)

msync — synchronize a mapped region

msync(caddr_t addr, int len);

The () system call writes any modified pages back to the filesystem and updates the file modification time. If len is 0, all modified pages within the region containing addr will be flushed; if len is non-zero, only the pages containing addr and len succeeding locations will be examined. Any required synchronization of memory caches will also take place at this time. Filesystem operations on a file that is mapped for shared modifications are unpredictable except after an msync().

The following errors may be reported:

[]
The addr parameter was not page aligned.
[]
The addr parameter did not specify an address part of a mapped region.
[]
The len parameter was negative.
[]
An I/O error occured while writing to the file system.

madvise(2), munmap(2), mprotect(2), mincore(2)

The msync() function first appeared in 4.4BSD.

4.4BSD-Lite2 June 21, 1994 MSYNC(2)