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Re: how to create and hardware watchpoint from a commands list.
- From: Doug Evans <xdje42 at gmail dot com>
- To: Julien Chavanton <jchavanton at gmail dot com>
- Cc: gdb <gdb at sourceware dot org>
- Date: Sun, 8 Feb 2015 13:47:33 -0800
- Subject: Re: how to create and hardware watchpoint from a commands list.
- Authentication-results: sourceware.org; auth=none
- References: <CAKmcL2mg7F3QZXvQPdzUfokHm15YKLar_XL_KZpdCNZ2i6N6+Q at mail dot gmail dot com> <CAP9bCMQknJ15bb52HPPq8ESa+=JOdhAxK=fTd45hxKVsep0qkQ at mail dot gmail dot com> <CAKmcL2kkSkTGrTdWWfz2ExtJygahYw7DML5JuT66RpuWXvtW_w at mail dot gmail dot com>
On Sun, Feb 8, 2015 at 6:49 AM, Julien Chavanton <jchavanton@gmail.com> wrote:
> Hi Doug, thank you for trying to help, I spent a few hours on this so
> I am interested to solve this puzzle for next time.
>
> ----------------------------
> By doing it manually I mean,
>
> step-1) I type :
>
> printf "0x%x\n", &call->stream->session->ext.settings.mode
>
> and then :
>
> step-2) I type :
> watch *(int *){result from step 1}
>
> -------------------------------
> This did not work for me :
>
> watch -location call->stream->session->ext.settings.mode
> -------------------------------
Without more details it's hard to help.
Can you provide a cut-n-paste of the gdb session that shows the problem?
>
> I can rerun the session and provide exact output or I could just try
> an alternative "piping" the output of step-1 to step-2 from the GDB
> "command line interpreter" not sure how it is called, this as to be
> executed from a breakpoint command list ?
>
>
> On Sun, Feb 8, 2015 at 5:26 AM, Doug Evans <xdje42@gmail.com> wrote:
>> On Wed, Feb 4, 2015 at 2:14 AM, Julien Chavanton <jchavanton@gmail.com> wrote:
>>> Hi Folks, I would like to create and hardware watchpoint from a commands list.
>>>
>>> retrieve the addres of a variable and create a watch.
>>>
>>> watch *(int *) &call->stream->session->ext.settings.mode
>>>
>>> Manualy this is working fine, but I do not know the right syntax in GDB.
>>
>> What do you mean by this working manually but then not knowing the right syntax?
>>
>>>
>>> I tried "watch -location call->stream->session->ext.settings.mode"
>>>
>>> And sereval other things, is there a way to pipe the output of one
>>> command to another one ?
>>
>> You tried several things, but you need to be more specific about
>> what problems you had. Complete unedited session logs are useful.
>>
>> There are various ways to "pipe" (for lack of a better term) the
>> output of previous commands into subsequent commands.
>> value history, convenience variables and/or eval or python come to mind.
>> But do you need to?
>> What about "watch -location ..." didn't work?
>>
>>>
>>> watch *(int *) | printf "0x%x\n", &call->stream->session->ext.settings.mode
>>>
>>>
>>> ----------------------------------------------------------
>>>
>>>
>>> define myhook
>>> echo myhook \n
>>> next
>>> next
>>> next
>>> print call->stream->session->ext.settings.mode
>>> print &call->stream->session->ext.settings.mode
>>> printf "watch *(int *)0x%x\n", &call->stream->session->ext.settings.mode
>>> end
>>>
>>> break set_settings
>>> commands
>>> myhook
>>> end