Re: The threads saga: watchpoints

[Elena Zannoni <ezannoni at redhat dot com>]

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