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Re: [patch] Indirect access to GDB history variables
- From: Eli Zaretskii <eliz at gnu dot org>
- To: Steve Rodrigues <steverod at netapp dot com>
- Cc: gdb-patches at sources dot redhat dot com
- Date: Fri, 15 Dec 2006 10:43:05 +0200
- Subject: Re: [patch] Indirect access to GDB history variables
- References: <20061215024050.GA8750@linden.netapp.com>
- Reply-to: Eli Zaretskii <eliz at gnu dot org>
> Date: Thu, 14 Dec 2006 18:40:50 -0800
> From: Steve Rodrigues <steverod@netapp.com>
> Cc: Steve Rodrigues <steverod@netapp.com>
>
> New Feature for GDB: Programmatic access to the value history.
>
> Problem Description: Our company has a wide variety of GDB scripts used to
> analyze problems within core files. Many of these scripts will generate values
> that are useful to probe into later; however, the scripts will generate a LOT
> of values, or values that aren't in sequential order (you care about, say,
> every third value). GDB only lets you reference previous history value either
> with absolute numbers ($10, $236) or with reference to the most recently printed value ($$, $$9, etc). It sure would be nice if there was a way to be able to
> access the value history by indirecting through a variable.
Why can't you put the values you are interested in into a named
variable, like $foo, and use that?
> Feature: This patch enables users to programmatcially access the value history
> through a GDB variable, by overloading the "$$" construct to contain a variable
> name. For example, if my script had printed out values $10-$27, but only every
> 3rd one was interesting (it was a pointer I wished to examine further), I could
> do the following:
>
> set $i=10
> while ($i < 28)
> p *$$i
> set $i+= 3
> end
>
> ... and I'd see values of $10, $13, $16 and so on. This makes it easier to
> compose scripts together when debugging.
Thanks.
If this patch is accepted, I will request you to write a patch for
the manual to describe this feature. It should also be mentioned in
NEWS.