Is GIOChannel thread-safe?

[Jonas Borgström <jonas codefactory se>]

Hi,

I'm having some problems using the glib event loop and iochannels
in a multi-threaded application. The documentation states:

"To allow multiple independent sets of sources to be handled in
 different threads, each source is associated with a GMainContext. 
 A GMainContext can only be running in a single thread, but sources can
 be added to it and removed from it from other threads."

The application segfaults or hangs after running for a while on SMP
machines.
I've managed to reproduce this on both linux 2.2 (2 cpu:s) and solaris
(4 cpu:s)

A simple test-case that triggers this issue on SMP machines can be found
here. Or is this test-case doing something "illegal"?

http://afs.codefactory.se/~jonas/roadrunner/gsource-test.c

This test-case segfaults after a few seconds on the solaris box and
within
a minute on the linux machine. I haven't been able to reproduce this on
single cpu machines.

I'm not sure what causes this, but it looks like it can have something
to do with that g_io_channel_ref/unref aren't thread-safe.

http://afs.codefactory.se/~jonas/roadrunner/giochannel.c-workaround.diff

This patch adds a static mutex around the ref and unref functions and
that seems to fix this issue, but it is probably not the correct/best 
solution.

So, what do you think, is this a bug or is gsource-test.c doing
something
"illegal"?

(I'm using glib-2.2.1)

Regards,
Jonas
-- 
Jonas Borgström                  jonas codefactory se
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