From:	CSBVAX::MRGATE!INFO-VAX-RELAY@KL.SRI.COM@SMTP  9-JUN-1988 21:22
To:	ARISIA::EVERHART
Subj:	Re: Can I set an AST for BRDCST messages?


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Date:      Sat,  4 Jun 88 10:55:26 CDT
To:        <INFO-VAX@KL.SRI.COM>
From:      "John Hascall" <GG.SPY%ISUMVS.BITNET@CUNYVM.CUNY.EDU>
Subject:   Re: Can I set an AST for BRDCST messages?

> Date:         Thu, 2 Jun 88 19:09:00 O
> Sender:       INFO-VAX Discussion <INFO-VAX@UBVM>
> From:         TENE@TECHMAX
> Subject:      Can I set an AST for BRDCST messages?
> To:           John Hascall <GA.JPH@ISUMVS>
>
> I am looking for a way to set an AST for receiving a broadcast message
> from $BRKTHRU and handling it. I know its possible because TPU seems
> to do it nicely but I can't find how. Since I want to handle the
> message SET BROADCAST is not enough, and since the message is an
> asynchronous event I assume I need an AST.
>
> What kind of AST is it?
> HOW do I set such an AST?
>
> Does anybody have any clues?
>

      1) use SYS$CREMBX to create a mailbox (and assign a channel to it)
      2) use SYS$ASSIGN to assign a channel to the terminal and associate
             the mailbox to the terminal
      3) use SYS$QIOW specifying the mailbox_channel and function
             IO$_SETMODE+IO$M_READATTN and an AST_RTN

      now in the AST_RTN you will need to
          1) read the mailbox channel using SYS$QIOW (the format of the
             message is in the I/O user's refernece manual Vol 1 in
             either the terminal driver or mailbox driver section)
          2) re-enable the READATTN as in 3) above

John Hascall
Iowa State Univ Computation Center
Ames, Iowa