From: Chris Sharman [Chris.Sharman@CCAgroup.co.uk]
Sent: Tuesday, March 27, 2001 5:32 AM
To: Info-VAX@Mvb.Saic.Com
Subject: Re: Such a thing as a 'nobackup' ACE?

Jan Vorbrueggen wrote:
> 
> adrian_parker@my-deja.com writes:
> 
> > Is there a way to make newly created files within a directory have a nobackup
> > attribute. I cannot find a reference to a default nobackup ACE which is how
> > i'd expected to do this. As it is, we're doing a set file/nobackup after
> > creation.
> 
> That certainly is the supported way. I do not think there is such an ACE -
> 
> Setting this from a program is a little work. Let RMS open the file for you,
> with the FAB option UFO (user file open). THe STV entry in the FAB then
> contains a channel you can use for a $QIO. Look in the parent manual of the
> quote above how to do a MODIFY (IIRC) with an ATR block that sets the NOBACKUP
> characteristic. You might need to read them first.

Easier to use XABITM XAB$_UCHAR_NOBACKUP with the RMS $create. You don't
need to get into $qio unless you want to do it to an existing file.
Below is a Pascal OPEN user_action function I use for the multitude of
large postscript files we generate daily.

Chris

    FUNCTION set_nobackup ( VAR fab: fab$type;
			    VAR rab: rab$type;
			    VAR f: TEXT ): UNSIGNED;
	VAR
	    sts: UNSIGNED;
	    enabl: INTEGER VALUE xab$k_enable;
	    itm: _item_list_3(1) VALUE ZERO;
	    xab: xab$type VALUE [
		xab$b_bln: xab$c_itmlen; xab$b_cod: xab$c_itm;
		xab$b_mode: xab$k_setmode;
		OTHERWISE ZERO];
	BEGIN
	WITH itm, item[1] DO
	    BEGIN
	    buf_len := SIZE(enabl);
	    code := xab$_uchar_nobackup;
	    buf_addr := IADDRESS(enabl);
	    END;
	xab.xab$l_itemlist := IADDRESS(itm.item[1]);
	xab.xab$l_nxt := fab.fab$l_xab;
	fab.fab$l_xab := IADDRESS(xab);
	sts := $create(fab);
	IF ODD(sts) THEN sts := $connect(rab);
	fab.fab$l_xab := xab.xab$l_nxt;
	set_nobackup := sts;
	END;