Re: [PATCH][PR guile/17247] Block SIGCHLD while initializing Guile

[ludo@gnu.org (Ludovic Courtès)]

Eli Zaretskii <eliz@gnu.org> skribis:

>> From: Doug Evans <xdje42@gmail.com>
>> Cc: ludo@gnu.org,  guile-devel@gnu.org,  gdb-patches@sourceware.org
>> Date: Fri, 05 Sep 2014 01:26:28 -0700
>> 
>> we can't physically prevent [users] from starting threads.
>
> Of course we can: if Guile gives us a way to disable threads, any user
> extension that attempts to start a thread will simply fail.

What Guile provides is a configure-time switch to disable threads (the
default is to enable threads.)  However, I would find it unacceptable to
require GDB users to have a specially-configured Guile.

What I would suggest is to strongly warn against the use of threads in
the manual.  If users ignore that warning, I think it’s their problem.

We might be able to annihilate thread functionality, for instance by
‘set!’ing the relevant bindings in Guile when GDB starts up.  But that’s
fragile and it misses the point: that users are free to run whatever
code they want anyway, and have plenty of other ways to mess up with GDB
(the same applies to Python extensions.)

(Besides, I agree with Pedro that the long-term vision should be to
eventually permit multi-threaded extensions, although I understand that
it won’t happen overnight.)

Thanks,
Ludo’.