Re: Emitting signals from threads

[Mitko Haralanov <voidtrance gmail com>]

Hi Chris,

I am not expecting g_idle_add() to emit the signal. I am calling a
separate function scheduled by g_idle_add() or
g_main_context_invoke_full(), which does the signal emission. I use
g_idle_add()/g_main_context_invoke_full() to ensure that this callback
is, in fact, running in the main context thread.

However, despite the signal emission occurring in the main context
thread, the signal handler seems to be running at the same time as GTK
internal functions are updating the state of the TreeView columns. As
I understand GTK, this should not be possible.

- Mitko

On Wed, Feb 27, 2019 at 1:10 PM Chris Vine via gtk-list
<gtk-list gnome org> wrote:
> On Wed, 27 Feb 2019 09:49:43 -0800
> Mitko Haralanov via gtk-list <gtk-list gnome org> wrote:
> [snip]
> > However, as I understand it, if my signal is running in the main
> > context, the signal handler should not be running at the same time as
> > Gtk is recalculating/repainting the TreeView. It seems as if the
> > threaded signal handler is not running in the main context. The above
> > behavior is replicated even if I switched to use g_idle_add() instead
> > of g_main_context_invoke_full().
>
> I am not going to try to penetrate your code, and you may already know
> this but a GObject signal handler executes in the thread which emits on
> the signal.  If this is a GDK/GTK+ signal, this would/should be, in
> almost all cases, the thread in which GTK+ runs, namely the thread
> of the default main context.
>
> g_idle_add() does not of itself emit a signal.  It executes a callback
> in the main loop of the default main context.
>
> Chris
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