man.bsd.lv manual page server

Manual Page Search Parameters
MSYNC(2) System Calls Manual MSYNC(2)

msync — synchronize a mapped region

library “libc”

#include <sys/types.h>
#include <sys/mman.h>

int
msync(void *addr, size_t len, int flags);

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 those pages containing addr and len-1 succeeding locations will be examined. The flags argument may be specified as follows:
Return immediately
Perform synchronous writes
Invalidate all cached data

The msync() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

msync() will fail if:

[]
addr is not a multiple of the hardware page size.
[]
len is too large or negative.
[]
flags was both MS_ASYNC and MS_INVALIDATE. Only one of these flags is allowed.
[]
An I/O error occurred while writing to the file system.

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

The msync() function first appeared in 4.4BSD.

June 21, 1994 DragonFly-5.6.1