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Subject: 
Re: signals / legOS internals
Newsgroups: 
lugnet.robotics.rcx.legos
Date: 
Wed, 23 Jun 1999 19:23:16 GMT
Viewed: 
945 times
  
Lou Sortman wrote:

Peek-a-boo!

I've been banging my head against this a bit and thought I'd see if any
of you can shove me in the right direction.  I am trying to implement
signals in legOS.  The problem is that a signal can happen at any time.
I know how to make that happen, but what is causing me trouble is that I
need to be able to put stuff on the stack.

Why signals?!?

Unix-style asynchronous signals is the last feature I would
ever want to implement or use. Brain-dead and very dangerous
"feature". As you write; "The problem is that a signal can
happen at any time". You shouldn't pass this problem on to the
application writer, it should be handled in the kernel and
reliable (synchronous) mechanisms (for instance semaphores,
message queues or OSE style message passing) should be presented
to the application.
--
       Ola Liljedahl           mailto:olli@enea.se
       Technical Manager
       Enea OSE Systems        http://www.enea.com



Message has 2 Replies:
  Re: signals / legOS internals
 
(...) An asynchronous signal models a hardware interrupt. There are times when that is the appropriate interface. There are times when other interfaces are less error prone and are easier to write correctly. Frequently using only synchronous (...) (25 years ago, 23-Jun-99, to lugnet.robotics.rcx.legos)
  Re: signals / legOS internals
 
(...) Because they are useful at times, and Markus directed me to implement them. I think the upcoming network code is going to use them, too (at least, that's what I heard). Just 'cause they're there doesn't mean you have to use them. (...) How do (...) (25 years ago, 23-Jun-99, to lugnet.robotics.rcx.legos)

Message is in Reply To:
  signals / legOS internals
 
Peek-a-boo! I've been banging my head against this a bit and thought I'd see if any of you can shove me in the right direction. I am trying to implement signals in legOS. The problem is that a signal can happen at any time. I know how to make that (...) (25 years ago, 23-Jun-99, to lugnet.robotics.rcx.legos)

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