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Re: The threads saga: watchpoints
- From: Elena Zannoni <ezannoni at redhat dot com>
- To: Daniel Jacobowitz <drow at mvista dot com>
- Cc: gdb at sources dot redhat dot com
- Date: Fri, 7 Mar 2003 09:41:33 -0500
- Subject: Re: The threads saga: watchpoints
- References: <20030307142230.GA20634@nevyn.them.org>
Daniel Jacobowitz writes:
> It was pointed out to me today that watchpoints and threads really don't get
> along. It's even in the manual:
>
> _Warning:_ In multi-thread programs, watchpoints have only limited
> usefulness. With the current watchpoint implementation, GDB can
> only watch the value of an expression _in a single thread_. If
> you are confident that the expression can only change due to the
> current thread's activity (and if you are also confident that no
> other thread can become current), then you can use watchpoints as
> usual. However, GDB may not notice when a non-current thread's
> activity changes the expression.
>
>
> I think some of our hardware breakpoint implementations have the same issue.
>
> It seems to me that, in general, this should be pretty easy to fix. But it
> requires some definite changes in the current infrastructure. Shouldn't we
> be able to insert the watchpoint in all threads?
>
> --
> Daniel Jacobowitz
> MontaVista Software Debian GNU/Linux Developer
There was a discussion on this some time ago:
http://sources.redhat.com/ml/gdb-patches/2002-01/msg00383.html
and follow-ups.
elena