FSYNC(2) BSD System Calls Manual FSYNC(2)NAMEfsync — synchronize a file's in-core state with that on disk
DESCRIPTIONFsync() causes all modified data and attributes of fd to be moved to a
permanent storage device. This normally results in all in-core modified
copies of buffers for the associated file to be written to a disk.
Fsync() should be used by programs that require a file to be in a known
state, for example, in building a simple transaction facility.
A 0 value is returned on success. A -1 value indicates an error.
The fsync() fails if:
[EBADF] fd is not a valid descriptor.
[EINVAL] fd refers to a socket, not to a file.
[EIO] An I/O error occurred while reading from or writing to
the file system.
SEE ALSOsync(2), sync(8), update(8)HISTORY
The fsync() function call appeared in 4.2BSD.
4.2 Berkeley Distribution June 4, 1993 4.2 Berkeley Distribution