RE: event masking

["Richard Jackson" <richardjackson@xxxxxxxxxxxxxxxxxx>]

The short answers are:

 

1. event masking is used to prevent an asynchronous program call from interrupting a particular section of code.  For example, it is considered rude and obnoxious for the OS code that handles page faults to have a page fault happen to it. 

 

2. When an event is masked, the action triggered by the event is either suppressed or delayed for a short time. 

 

3. You don't want to turn it off.  That would be bad.  Find another way. 

Richard Jackson
Richard Jackson and Associates Ltd. 
IBM Business Partner
mailto:richardjackson@richardjackson.net
http://www.richardjacksonltd.com
Telephone: 1 (303) 808-8058

-----Original Message-----
From: owner-mi400@midrange.com [mailto:owner-mi400@midrange.com]On Behalf Of Matt Bresnan
Sent: Wednesday, November 15, 2000 7:23 PM
To: MI400 List
Subject: event masking

Is anyone familiar with event masking?  It's something that the OS does and it prevents debugging, not sure if preventing debugging is the goal or just a side effect. 

 

The scenario is that I've tapped into an entry point in the SEPT and I'm trying to debug that program when called through the SEPT.  The breakpoint never displays and I get this strange message:

 

Cause . . . . . :   The breakpoint statement or instruction /0001 in

program TEST was already processed when the machine notification was received. The
  program call for the breakpoint may no longer exist.
Technical description . . . . . . . . :   The process was probably masked for

  events when the breakpoint instruction was run. You cannot use the ADDBKP
  command to stop the program at an instruction while the process is masked
  for events.

 

If my test program calls another program, I get the same error trying to debug the second program.  So I'm just looking for more information about this event masking, what it does, why it's used and if there is a way to turn it off. 

 

BTW, this is on a V4R4 box.

 

Thanks.

 

--Matt