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Conference bulova::decw_jan-89_to_nov-90

Title:	DECWINDOWS 26-JAN-89 to 29-NOV-90
Notice:	See 1639.0 for VMS V5.3 kit; 2043.0 for 5.4 IFT kit
Moderator:	STAR::VATNE

Created:	Mon Oct 30 1989
Last Modified:	Mon Dec 31 1990
Last Successful Update:	Fri Jun 06 1997
Number of topics:	3726
Total number of notes:	19516

1901.0. "why doesn't SET DISPLAY/USER work like DEFINE/USER" by HANNAH::OSMAN (see HANNAH::IGLOO$:[OSMAN]ERIC.VT240) Tue Dec 12 1989 15:54

(I also posted this in vaxwrk::vmsnotes and got no response)
    
    Could someone please explain why
    
    	SET DISPLAY/USER
    
    was designed *not* to delete the DECW$DISPLAY logical name after one
    DECwindows application ?  I think it should.
    
    It does throw away the WSA device to which the logical name
    refers, so the logical name is rather useless at this point it seems
    to me.
    
    Not only is the name useless, you get a "can't open display" error when
    you next run any program that tries to look for DECW$DISPLAY.  If the
    name had been thrown away, all would be better.
    
    Compare with
    
    	DEFINE/USER name ...
    
    The nicely throws away the name after one program is run.
    
    Here's my typical usage, which the above problem is causing an error
    on:
    
    	$ set display/user ...
    	$ run my-test
    	<later>
    	$ notes
    
    I get
    
    	Can't open display
    
    from notes.  I expect notes to run regular CHARACTER CELL version.
    I used "/user" on my SET DISPLAY because I ONLY want the SET
    DISPLAY to apply to "my-test".  isn't that what it's for ?
    
    Thanks for some insight as to why it works the way it does
    (or admission of guilt :-)
    
    
    /Eric

T.R Title User Personal
Name Date Lines

1901.1 user mode logical name deleted as part of image rundown? VMSDEV::BALLOU It's not slow, it's careful! Wed Dec 13 1989 00:14 6

T.R	Title	User	Personal Name	Date	Lines
1901.1	user mode logical name deleted as part of image rundown?	VMSDEV::BALLOU	It's not slow, it's careful!	`Wed Dec 13 1989 00:14`	6
	If I had to guess, I would say that "$ SET DISPLAY" invokes the image SYS$SYSTEM:DECW$SETSHODIS.EXE. Now, I would figure that the image does indeed define a logical name in user mode, but that image rundown causes the user mode logical name to be deleted before returning to DCL. By comparison, "$ DEFINE" is an "internal" DCL command which does not cause an image to be activated [see page 638 of the IDSM -- I just did to make sure this is a true statement :-]

If I had to guess, I would say that "$ SET DISPLAY" invokes the image
SYS$SYSTEM:DECW$SETSHODIS.EXE.  Now, I would figure that the image does indeed
define a logical name in user mode, but that image rundown causes the user mode
logical name to be deleted before returning to DCL.  By comparison, "$ DEFINE"
is an "internal" DCL command which does not cause an image to be activated [see
page 638 of the IDSM -- I just did to make sure this is a true statement :-]