sub PDL::mapfraw {
        my $class = shift;
	my($name,$opts) = @_;
	my $hdr;
	if($opts->{Dims}) {
		my $datatype = $opts->{Datatype};
		if(!defined $datatype) {$datatype = $PDL_D;}
		$hdr->{Type} = $datatype;
		$hdr->{Dims} = $opts->{Dims};
		$hdr->{NDims} = scalar(@{$opts->{Dims}});
	} else {
		$hdr = _read_frawhdr($name);
	}
	$s = PDL::Core::howbig($hdr->{Type});
	for(@{$hdr->{Dims}}) {
		$s *= $_;
	}
	my $pdl = $class->zeroes(new PDL::Type($hdr->{Type}));
#	$pdl->dump();
	$pdl->setdims($hdr->{Dims});
#	$pdl->dump();
	$pdl->set_data_by_mmap($name,$s,1,($opts->{ReadOnly}?0:1),
		($opts->{Creat}?1:0),
		(0644),
		($opts->{Creat} || $opts->{Trunc} ? 1:0));
#	$pdl->dump();
	if($opts->{Creat}) {
		_writefrawhdr($pdl,$name);
	}
	return $pdl;
}


##</code><code>##

set_data_by_mmap(it,fname,len,writable,shared,creat,mode,trunc)
	pdl *it
	char *fname
	int len
	int writable
	int shared
	int creat
	int mode
	int trunc
	CODE:
#ifdef USE_MMAP
       int fd;
       pdl_freedata(it);
       fd = open(fname,(writable && shared ? O_RDWR : O_RDONLY)|
               (creat ? O_CREAT : 0),mode);
       if(fd < 0) {
               croak("Error opening file");
       }
       if(trunc) {
               ftruncate(fd,0);   /* Clear all previous data */
               ftruncate(fd,len); /* And make it long enough */
       }
       if(len) {
		it->data = mmap(0,len,PROT_READ | (writable ?
					PROT_WRITE : 0),
				(shared ? MAP_SHARED : MAP_PRIVATE),
				fd,0);
		if(!it->data)
			croak("Error mmapping!");
       } else {
               /* Special case: zero-length file */
               it->data = NULL;
       }
       PDLDEBUG_f(printf("PDL::MMap: mapped to %d\n",it->data);)
       it->state |= PDL_DONTTOUCHDATA | PDL_ALLOCATED;
       pdl_add_deletedata_magic(it, pdl_delete_mmapped_data, len);
       close(fd);
#else