MSYNC(2) BSD System Calls Manual MSYNC(2)NAMEmsync — synchronize a mapped region
Standard C Library (libc, -lc)
msync(void *addr, size_t len, int flags);
The msync() system call writes modified whole pages back to the filesys‐
tem and updates the file modification time. Only those pages containing
addr and len-1 succeeding locations will be examined. The flags argument
may be specified as follows:
MS_ASYNC Return immediately
MS_SYNC Perform synchronous writes
MS_INVALIDATE Invalidate all cached data
The MS_ASYNC flag is not permitted to be combined with other flags.
If any errors occur, -1 is returned and errno is set to indicate the
error. Otherwise, a 0 value is returned.
ERRORSmsync() will fail if:
[EINVAL] addr is not a multiple of the hardware page size.
[EINVAL] len is too large, or less than 1.
[EINVAL] flags combined MS_ASYNC with another flag, which is
[EIO] An I/O error occurred while writing to the file sys‐
SEE ALSOmadvise(2), mincore(2), mprotect(2), munmap(2)HISTORY
The msync() function first appeared in 4.4BSD.
BSD June 21, 1994 BSD