FSYNC(2)                  OpenBSD Programmer's Manual                 FSYNC(2)

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



SYNOPSIS
     #include <unistd.h>

     int
     fsync(int fd);

DESCRIPTION
     fsync() 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.

RETURN VALUES
     A 0 value is returned on success.  A -1 value indicates an error.

ERRORS
     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 ALSO
     sync(2),  sync(8),  update(8)

HISTORY
     The fsync() function call appeared in 4.2BSD.

OpenBSD 2.6                      June 4, 1993                                1