Path: csiph.com!usenet.pasdenom.info!dedibox.gegeweb.org!gegeweb.eu!nntpfeed.proxad.net!proxad.net!feeder1-2.proxad.net!usenet-fr.net!nerim.net!novso.com!newsfeed.xs4all.nl!newsfeed3.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: quoted-printable
From: David Froger <david.froger@inria.fr>
User-Agent: alot/0.3.5
To: python-list@python.org
References: <mailman.2274.1383962639.18130.python-list@python.org> <e4e2892f-76a6-43a8-b59d-42ee01dfa023@googlegroups.com>
In-Reply-To: <e4e2892f-76a6-43a8-b59d-42ee01dfa023@googlegroups.com>
Subject: Re: Conditional breakpoints in ceval.c
Date: Tue, 12 Nov 2013 09:44:22 +0100
Precedence: list
Newsgroups: comp.lang.python
Message-ID: <mailman.2436.1384246441.18130.python-list@python.org>
Lines: 65
NNTP-Posting-Host: 2001:888:2000:d::a6
Xref: csiph.com comp.lang.python:59164

Quoting Ned Batchelder (2013-11-09 14:24:34)
> On Friday, November 8, 2013 9:03:51 PM UTC-5, Demian Brecht wrote:
> > Hi all,
> > =

> > I have an .py file with a simple assignment in it:
> > foo =3D 'bar'
> > =

> > Now, I want to set a conditional breakpoint in gdb, breaking on that
> > assignment (I'm guessing the top of the stack would be breaking on the
> > LOAD_CONST with a value or 'bar'). How would I go about doing that?
> > =

> > b ceval.c:1368 if [?]
> > =

> > Thanks,
> > =

> > -- =

> > Demian Brecht
> > http://demianbrecht.github.com
> =

> I don't know how to use gdb the way you want, but it sounds like you are =
on a fascinating journey of discovery.  What are you trying to learn?  Perh=
aps we can talk about how the interpreter works.
> =

> --Ned.
> -- =

> https://mail.python.org/mailman/listinfo/python-list

Hi all,

In the purpose of debugging C/C++ Python extensions, I've been also looking=
 for
a way to put a gdb breakpoint on a Python line file, like this:
    (gdb) b foo.py:47
But I have no idea how this could be implemented.

To break in a C/C++ extension with gdb, on can declare a function, for
example 'Py_DebugTrap' [1], and call it call in the C/C++ code where he/she
want to break, then in gdb:
    (gdb) b Py_DebugTrap

So a altenative to break into Python could be to do the same: wrap the
Py_DebugTrap in a Python module, then in the Python file, call the trap
function, for example:
    import gdbbreak
    gdbbreak.breakpoint_here()
    foo =3D 'bar'

The function gdbbreak.breakpoint_here() would just call the 'Py_DebugTrap'
function, and then in gdb:
    (gdb) b Py_DebugTrap
    (gdb) next # until foo =3D 'bar' assignement is reach

(I never try this, be it should work.)

[1] http://joyrex.spc.uchicago.edu/bookshelves/python/cookbook/pythoncook-C=
HP-16-SECT-8.html