GThread usage in the panel
Brian J. Tarricone
bjt23 at cornell.edu
Sat Jul 24 20:45:19 CEST 2004
Benedikt Meurer wrote:
> Jasper Huijsmans wrote:
>> Hey all, especially plugin writers,
>> Yesterday, I committed a patch from Brian that adds thread
>> initialization and locking to the panel.
>> I had hoped that this would not affect anything that wasn't using
>> threads, but it seems this is not the case: idle or timeout functions
>> need to use gdk_thread_enter (); ...; gdk_thread_leave(); to make
>> sure there is no conflict with other threads accessing gtk.
>> Since there are currently no plugins using threads, this problem
>> won't show up yet, but it will when e.g. the menu plugin starts using
>> If you implement this you can depend on the panel version 4.1.7.
> To easy the transition, I added some magic to the XFCE_PANEL_PLUGIN m4
> macro. It now tests if the panel is threaded and if so, it defines
> XFCE_PANEL_THREADED=1 and sets XFCE_PANEL_LOCK to gdk_threads_enter
> and XFCE_PANEL_UNLOCK to gdk_threads_leave. If the panel isn't
> threaded, XFCE_PANEL_THREADED won't be defined and XFCE_PANEL_(UN)LOCK
> will be no-ops.
> So, for panel plugin writers:
> 1) get the latest depends.m4 from Xfce CVS (I've already updated the
> depends.m4 files in berlios CVS, so if your plugin is hosted at the
> xfce-goodies project, you don't need this step)
> 2) Locate idle/timeout functions and place XFCE_PANEL_LOCK() at the
> beginning of the function and XFCE_PANEL_UNLOCK() at the end of the
> function (_before_ the return of course :-).
an important note. this means you CANNOT use these functions for
anything but idle/timeout functions. if you call one of these functions
from anywhere in the main thread or in the gtk main loop, the panel will
hang. if you have a function that you use as a timeout/idle function
and that you just call normally, you'll need to wrap it in another
function that calls XFCE_PANEL_LOCK/UNLOCK() around the function call.
sorry i'm not explaining this perfectly, but if anyone's confused, let
me know and i'll provide an example.
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