# Interface from Perl filehandle to POSIX file descriptor.
sub fsync(*) {
    @_ == 1 or croak "usage: fsync FILEHANDLE";

    fsync_fd(fileno(qualify_to_ref($_[0], caller())));
}

# Make fsync a method of IO::Handle and FileHandle.
*IO::Handle::fsync = *FileHandle::fsync = \&fsync;