FSYNC(2-SVR4)       RISC/os Reference Manual        FSYNC(2-SVR4)



NAME
     fsync - synchronize a file's in-memory state with that on
          the physical medium

SYNOPSIS
     #include <unistd.h>

     int fsync(int fildes);

DESCRIPTION
     fsync moves all modified data and attributes of fildes to a
     storage device.  When fsync returns, all in-memory modified
     copies of buffers associated with fildes have been written
     to the physical medium.  fsync is different from sync, which
     schedules disk I/O for all files but returns before the I/O
     completes.

     fsync should be used by programs that require that a file be
     in a known state.  For example, a program that contains a
     simple transaction facility might use fsync to ensure that
     all changes to a file or files caused by a given transaction
     were recorded on a storage medium.

     fsync fails if one or more of the following are true:

     EBADF          fildes is not a valid file descriptor open
                    for writing.

     ENOLINK        fildes is on a remote machine and the link on
                    that machine is no longer active.

     EINTR          A signal was caught during execution of the
                    fsync system call.

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

DIAGNOSTICS
     Upon successful completion, a value of 0 is returned. Other-
     wise, a value of -1 is returned and errno is set to indicate
     the error.

NOTES
     The way the data reach the physical medium depends on both
     implementation and hardware.  fsync returns when the device
     driver tells it that the write has taken place.

SEE ALSO
     sync(2)






                        Printed 11/19/92                   Page 1