Re: froggy/archer -- 2009-02-24

[Chris Moller <cmoller at redhat dot com>]

Daniel Jacobowitz wrote:
> On Tue, Feb 24, 2009 at 11:01:08AM -0500, Chris Moller wrote:
>   
>> The problem is that there's no way to fit that dual-thread/callback
>> paradigm into existing gdb--I've been tearing my hair out for a couple
>> of weeks trying to make it happen.
>>     
>
> Could you expand on this a little?  It does not sound all that
> different from the signal-based mechanism that GDB uses for async and
> non-stop debug (I'm assuming you're looking at HEAD).
>   

The problem is that there are waitpid() instances in a lot of places,
all of them blocking, and then dealing with whatever happens to break
the block.  The architecture of froggy is such that it expects to be the
sole handler of inferior-process events that break waitpid() blocks on,
and do so on a thread dedicated to that.  So far as I can tell, the only
way to make this work in existing gdb is to implement some other kind of
blocking in the gdb waitpid()s and have froggy callbacks tickle them as
necessary.  This looks like it would not only be hard to do, but
wouldn't really add any capability to what's there already.

-- 
Chris Moller

  I know that you believe you understand what you think I said, but
  I'm not sure you realize that what you heard is not what I meant.
      -- Robert McCloskey

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