From:	MERC::"uunet!CRVAX.SRI.COM!RELAY-INFO-VAX" 20-JUN-1992 07:53:47.62
To:	info-vax@kl.sri.com
CC:	
Subj:	Re: $GETUAI system service call - context?

In article <01GKRW0HHRF48WW45E@ACC.HAVERFORD.EDU>, MONITOR@ACC.HAVERFORD.EDU (Haverford College Monitor Account) writes:
> 
>      A while ago I remember hearing something about an undocumented 
> "context" field in the $GETUAI system service call, to speed up repeated 
> calls. Can anyone tell me anything about this?
>      			Thanks,
>      				Ethan Shayne
>      				Student VAX Manager
>      				Haverford College
> 
> 
>      		Bitnet:		vax_mgr@hvrford
>      		Internet:	vax_mgr@acc.haverford.edu

Last year I wrote a somewhat large and complicated utility for reporting on
or modifing users found by various combinations of UAF fields. Here is a BASIC
program segment from that utility illustrating this feature.
(GETUAI_CONTEXT is a LONGWORD).

    ! Initialize The Context For SYS$GETUAI. This Context, At The Time
    ! Of Writing Is An Undocumented Feature Of SYS$GETUAI, But Is Used
    ! To Hold The SYSUAF Open Over Repeated Calls As We Don't Want To
    ! Open And Close The SYSUAF For Each User Processed.
 
    LET GETUAI_CONTEXT=-1%
 
    ! Loop Through All The Users Supplied By GET_USER_NAMES
 
    FOR NUM_USERS_MATCH=0% TO NUM_USERS_MATCH
 
        ! Put A Message On The Display Informing The User
        ! About What User We Are Comparing (Current User)
 
        CALL SMG$PUT_CHARS(QUEST_DISPLAY, "Comparing " + &
            USERS_MATCH(NUM_USERS_MATCH)+ &
            SPACE$(32%-LEN(USERS_MATCH(NUM_USERS_MATCH))), 13%, 30%,, )
 
        ! Get The Current User
 
        LET UAI_STAT=SYS$GETUAI(,GETUAI_CONTEXT,USERS_MATCH(NUM_USERS_MATCH) &
            BY DESC, GETUAI BY REF,,,)

Hope this helps. I found out about this trick from reading the VMS source
listing microfiche as without this feature SYS$GETUAI is way to slow and
causes to much overhead to be usefull when processing large amounts of users.

				Patrick Young
				VAX/VMS Group 
				University Of New South Wales