fsync(2)                                                       fsync(2)

  fsync()

  NAME

    fsync() - synchronize disk and in-memory versions of a file

  SYNOPSIS

    #include 

    int fsync (int fd)

  DESCRIPTION

    The fsync(2) call flushes the buffer for the specified file descriptor
    causes all modified data and attributes of fd to be moved to a permanent
    storage device. It flushes to disk the buffers for the specified file
    descriptor.

    Use fsync(2) in programs that require a file to be in a known state, for
    example, in building a simple transaction facility.

  RETURN VALUES

    The fsync(2) call returns 0 for success. On an error, it returns -1 and
    sets errno to indicate the error.

  ERRORS

    The fsync(2) call fails for the following reasons:

    [EBADF]
        The file descriptor fd was invalid.

    [EINTR]
        The function was interrupted by a signal.

    [EINVAL]
        The file referred to by fd doesn't support the operation.

    [EIO]
        An I/O error occurred.

  USAGE NOTES

    The fsync function is thread safe.

    The fsync function is async-signal safe.