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Question asked by VRFuser on Jan 30, 1997
send q VRF-Multithreading vrf

from: Greg Goebel / HP-MXD / 970-679-3030 / FAX 970-679-5971
to:   VRf-Sergei Ermolin
date: Friday, 31 January 1997 1544 MST

>      Thank you, Alex.
>      Maybe, you can give me another hint:
>      I am creating a real-time application.  In short, I need to sample
>      frequencies of 256 devices under test (DUTs) every 7 min +/- 15 sec and
>      also communicate with them via RS-232 port using IEEE-488 GPIB
>      controlled switching network.  On top of that, there may be a
>      considerable data reduction and operator data entry activity going on at
>      the same time.  The way I intend to implement that is by using multiple
>      threads (one for frequency sampling, one for RS-232 communications, one
>      for data analysis, one for operator interface refreshing, etc).
> The question is:  how do I make frequency sampling thread to be the first
> priority in execution, so that I measure frequency in specified time
> intervals? 

You can't really prioritize thread operations specifically; that would
imply determinism, which means that you want to do everything in one thread.
Please check the VEE tutorial I wrote on our netsite ... internal people
can get to it at:


  -> PCTM Support -> VEE Tutor

The chapter on VEE control flow should give you some ideas on what to do.

> Also, is there any way to prevent RS-232 communication objects
> from locking up the system until they recieve appropirate response or
> time-out?

Unfortunately, I/O won't multitask ... if you do a timeout wait, nothing else
runs in that copy of VEE.

> Regards,
> Sergey Ermolin

If you have more questions, let us know.

[<>] regards -- gvg