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Re: Watchpoints with condition
- From: Eli Zaretskii <eliz at gnu dot org>
- To: Vladimir Prus <vladimir at codesourcery dot com>
- Cc: gdb at sources dot redhat dot com
- Date: Fri, 30 Nov 2007 23:15:51 +0200
- Subject: Re: Watchpoints with condition
- References: <200711301925.20196.vladimir@codesourcery.com>
- Reply-to: Eli Zaretskii <eliz at gnu dot org>
> From: Vladimir Prus <vladimir@codesourcery.com>
> Date: Fri, 30 Nov 2007 19:25:19 +0300
>
>
> GDB presently allow a watchpoint to have a condition, and I wonder
> what are the use-cases for that.
>
> If anybody has used watchpoint in condition in practice when debugging
> real problem (as opposed to just playing with gdb, or making up
> possible uses), can he share why it was needed?
I use it quite a lot. The simplest use case is like this:
(gdb) watch foo if foo == 1
This stops at the watchpoint only if the value written to the variable
is 1. Imagine that you need to find who writes a specific value into
a variable that is otherwise written into a lot by legitimate code.