ultrix man page for fsync

fsync(2)							System Calls Manual							  fsync(2)

Name
       fsync - synchronize a file's in-core state with that on disk

Syntax
       fsync(fd)
       int fd;

Description
       The system call causes all modified data and attributes of fd to be moved to a permanent storage device.  This results in all in-core modi-
       fied copies of buffers for the associated file to be written to a disk.

       The call should be used by programs that require a file to be in a known state, for example, in building a simple transaction facility.

Return Values
       A 0 value is returned on success.  A -1 value indicates an error.

Diagnostics
       The call fails under the following conditions:

       [EBADF]	      The fd argument is not a valid descriptor.

       [EINVAL]       The fd argument refers to a socket.

       [EIO]	      An I/O error occurred while reading from or writing to the file system.

       [EINTR]	      The function was interrupted by a signal.

       If an error occurs on an asynchronous write over NFS, the error cannot always be returned from a system call.  The error code  is  returned
       on or The following are NFS-only error messages:

       [EACCESS]      The requested address is protected, and the current user has inadequate permission to access it.

       [ENOSPC]       There is no free space remaining on the file system containing the file.

       [EDQUOT]       The user's quota of disk blocks on the file system containing the file has been exhausted.

       [EROFS]	      The file is on a read-only file system.

       [ESTALE]       The fd argument is invalid because the file referred to by that file handle no longer exists or has been revoked.

       [ETIMEDOUT]    A  write	operation  failed  because  the  server  did  not properly respond after a period of time that is dependent on the
		      options.

See Also
       sync(1), close(2), sync(2), write(2), update(8)

																	  fsync(2)