catch-throw conditions?

catch-throw conditions?

[Craig Miller]

Does anyone know if there is a way to set a condition on breakpoints
created using the "catch throw" command?  Specifically to be able to
only cause a break when a specific C++ Exception is thrown?

CentOS 4.5
gdb Red Hat Linux (6.3.0.0-1.143.el4rh)
gcc 3.4.6

Thanks for any help you might be able to lend.  I've hit a dead end
with google and the GDB docs.

Re: catch-throw conditions?

[Andrew STUBBS]

Craig Miller wrote:
> Does anyone know if there is a way to set a condition on breakpoints
> created using the "catch throw" command?  Specifically to be able to
> only cause a break when a specific C++ Exception is thrown?

In general, conditions work like this (not that the help command will 
tell you so):

	catch throw if myerror == 42

I'm not sure where the exception flavour is kept though.

Hope that helps

Andrew


(Actually, on the GDB I have the conditions do not show on info break, 
and I don't have any C++ code handy to test, so it might be broken. If 
the condition doesn't work then try this:

    catch throw
    commands
      if myerror != 42
        continue
      end
    end
)

Re: catch-throw conditions?

[Thiago Jung Bauermann]

On Thu, 2008-02-21 at 11:24 -0800, Craig Miller wrote:
> Does anyone know if there is a way to set a condition on breakpoints
> created using the "catch throw" command?  Specifically to be able to
> only cause a break when a specific C++ Exception is thrown?
> 
> CentOS 4.5
> gdb Red Hat Linux (6.3.0.0-1.143.el4rh)
> gcc 3.4.6
> 
> Thanks for any help you might be able to lend.  I've hit a dead end
> with google and the GDB docs.

I have absolutely no experience with gdb's C++ support, but I saw with
"help catch" that  gdb 6.7.1 (the current GDB release) has this command:

        catch throw <exceptname>  - a particular exception, when thrown

Is it available in your GDB version (which is very old, BTW)? If not, I
suggest obtaining the new GDB and trying it out.
-- 
[]'s
Thiago Jung Bauermann
Software Engineer
IBM Linux Technology Center

Re: catch-throw conditions?

[Daniel Jacobowitz]

On Fri, Feb 22, 2008 at 10:25:17AM -0300, Thiago Jung Bauermann wrote:
> I have absolutely no experience with gdb's C++ support, but I saw with
> "help catch" that  gdb 6.7.1 (the current GDB release) has this command:
> 
>         catch throw <exceptname>  - a particular exception, when thrown

"help catch", unfortunately, is incorrect :-(

IIRC this was implemented for HP aCC.  The GNU support does not (yet)
handle an exceptname.

-- 
Daniel Jacobowitz
CodeSourcery

Re: catch-throw conditions?

[Daniel Jacobowitz]

On Fri, Feb 22, 2008 at 09:19:40AM -0500, Daniel Jacobowitz wrote:
> "help catch", unfortunately, is incorrect :-(
> 
> IIRC this was implemented for HP aCC.  The GNU support does not (yet)
> handle an exceptname.

... But if someone is interested, this would not be a huge project.
Ada already supports something similar.

-- 
Daniel Jacobowitz
CodeSourcery

Re: catch-throw conditions?

[Doug Evans]

On Fri, Feb 22, 2008 at 6:24 AM, Daniel Jacobowitz <drow@false.org> wrote:
> On Fri, Feb 22, 2008 at 09:19:40AM -0500, Daniel Jacobowitz wrote:
>  > "help catch", unfortunately, is incorrect :-(
>  >
>  > IIRC this was implemented for HP aCC.  The GNU support does not (yet)
>  > handle an exceptname.
>
>  ... But if someone is interested, this would not be a huge project.
>  Ada already supports something similar.

Ok if I add something like the following to the ProjectIdeas page?
[what are the rules for editing the wiki btw?]

C++
 * Implement catching of specific exceptions.
   Currently GDB does not support specifying a catchpoint for a
particular exception.
   "catch catch" and "catch throw" work, but "catch catch exception_name"
   and "catch throw exception_name" do not.

[or some such]

Re: catch-throw conditions?

[Daniel Jacobowitz]

On Fri, Feb 22, 2008 at 09:36:50AM -0800, Doug Evans wrote:
> On Fri, Feb 22, 2008 at 6:24 AM, Daniel Jacobowitz <drow@false.org> wrote:
> > On Fri, Feb 22, 2008 at 09:19:40AM -0500, Daniel Jacobowitz wrote:
> >  > "help catch", unfortunately, is incorrect :-(
> >  >
> >  > IIRC this was implemented for HP aCC.  The GNU support does not (yet)
> >  > handle an exceptname.
> >
> >  ... But if someone is interested, this would not be a huge project.
> >  Ada already supports something similar.
> 
> Ok if I add something like the following to the ProjectIdeas page?
> [what are the rules for editing the wiki btw?]

There aren't any.  Far as I'm concerned you can add anything you want
:-)

Another useful thing would be to display the exception and to
automatically show the frame with the throw/catch.  I think Ada does
those, too.

-- 
Daniel Jacobowitz
CodeSourcery

Re: catch-throw conditions?

[Adrian Jones]

On 22/02/2008, Daniel Jacobowitz <drow@false.org> wrote:
> On Fri, Feb 22, 2008 at 09:36:50AM -0800, Doug Evans wrote:
>  > On Fri, Feb 22, 2008 at 6:24 AM, Daniel Jacobowitz <drow@false.org> wrote:
>  > > On Fri, Feb 22, 2008 at 09:19:40AM -0500, Daniel Jacobowitz wrote:
>  > >  > "help catch", unfortunately, is incorrect :-(
>  > >  >
>  > >  > IIRC this was implemented for HP aCC.  The GNU support does not (yet)
>  > >  > handle an exceptname.
>  > >
>  > >  ... But if someone is interested, this would not be a huge project.
>  > >  Ada already supports something similar.
>  >
>  > Ok if I add something like the following to the ProjectIdeas page?
>  > [what are the rules for editing the wiki btw?]
>
>
> There aren't any.  Far as I'm concerned you can add anything you want
>  :-)
>
>  Another useful thing would be to display the exception and to
>  automatically show the frame with the throw/catch.  I think Ada does
>  those, too.


I suppose just adding a breakpoint in the exception constructor is a
little hacky for what you are after here
-Adrian