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From: ludo@gnu.org (Ludovic Courtès)
To: Tom Tromey <tromey@redhat.com>
Cc: gdb-patches@sourceware.org,  guile-user@gnu.org
Subject: Re: [PATCH v2 02/13] script language API for GDB: extension.[ch]
Date: Tue, 07 Jan 2014 14:10:38 +0100	[thread overview]
Message-ID: <87eh4krl81.fsf@gnu.org> (raw)
In-Reply-To: <87r48kkc9g.fsf@fleche.redhat.com> (Tom Tromey's message of "Mon,	06 Jan 2014 14:53:47 -0700")

Tom Tromey <tromey@redhat.com> skribis:

>>>>>> "Ludovic" == Ludovic Courtès <ludo@gnu.org> writes:
>
> Ludovic> I’m not sure I understand the problem.
>
> Ludovic> What are extension languages typically expected to do when the ‘quit’
> Ludovic> flag is set?
>
> The basic idea is that if some extension code is running, then C-c ought
> to interrupt that code in the way expected by programmers writing code
> in that language.
>
> Python provides a kind of low-level API to its equivalent of Guile's
> SCM_TICK and async stuff.  So the approach we took in gdb was to unify
> gdb's implementation with Python's, when Python is enabled.  This
> ensures that a SIGINT delivery is handled a single time -- by Python if
> Python code is running, and by gdb if gdb code is running.

So do I get it right that it’s GDB that does signal(SIGINT, ...), and
its handler just calls PyOS_InterruptOccurred (or so) if Python code
happens to be running?

> One approach for multiple extension languages might be to notice when
> switching languages and move the bit.  However I didn't see any way to
> do this in the Guile API.  In Python it can be accomplished with
> PyErr_SetInterrupt and PyOS_InterruptOccurred.

Would it work, upon SIGINT, to do something like:

  (system-async-mark (lambda ()
                       (throw 'system-error ... EINTR)))

That would eventually raise an exception in Scheme code.

Ludo’.


  reply	other threads:[~2014-01-07 13:10 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <52a7f3e8.e7ed440a.1c58.020f@mx.google.com>
     [not found] ` <87vbyffcwu.fsf@fleche.redhat.com>
2013-12-24 18:05   ` [PATCH v2 02/13] script language API for GDB: extension.[ch] Doug Evans
2014-01-03 21:10     ` Ludovic Courtès
2014-01-06 21:53       ` Tom Tromey
2014-01-07 13:10         ` Ludovic Courtès [this message]
2014-01-07 16:02           ` Tom Tromey
2014-01-07 23:05             ` Ludovic Courtès
2014-01-08  3:17               ` Tom Tromey
2014-01-14 19:17               ` Tom Tromey
2014-01-15 14:52                 ` Ludovic Courtès
2014-01-22  4:21                 ` Mark H Weaver
2014-01-22  4:35                   ` Doug Evans

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