Re: Pause and resume GtkApplication

[Chris Vine <vine35792468 gmail com>]

On Fri, 26 Jan 2018 11:14:36 +0700
"Lucky B.C" <lblackc13 gmail com> wrote:
> Well, in the case, I will tell something about me, first I've never
> used the GtkApplication just main window maybe sub windows (dialogs)
> too, and my programs did not do as what you are trying to do. Second
> I'm a C programmer, in my opinion, you should redesign your app
> because sometimes we must do that to gain our main target not about
> GUI which we only need for rendering/displaying to the user. Nothing
> is perfect! If we don't want the user see the private data or
> something else, we just don't show it by doing in another thread.
> Yes, the main loop of GTK always runs after we called gtk_main (),
> but we can create another thread before gtk_init () is called and run
> it anytime we need by gdk_threads_enter and gdk_threads_leave, for
> more detail see GThreads
> <https://developer.gnome.org/glib/stable/glib-Threads.html#g-thread-new>
> and IDLES
> <https://developer.gnome.org/gdk2/stable/gdk2-Threads.html>. Finally
> just reload/refresh our new data/thing again to the user or show a
> message dialog says somthing else, for example "Your data changed!".
> I wonder is there some programs which have the same what you are
> trying to do? If there's one or more, please send me the link, I
> really want to test them.

gdk_threads_enter and gdk_threads_leave are absolutely not the way to
do it.  They are deprecated in GTK+3 and will be removed in GTK+4.
Furthermore they only work with the X backend (not with windows or
wayland) and are horribly error-prone.

The correct way for a worker thread to pass back a result to the glib
main loop, or to execute code in that loop, is for it to post an event
using g_idle_add() and cognates.  The glib main loop is thread safe.

gdk_threads_add_idle is only necessary if your code interfaces with
ancient third-party library code which uses gdk_threads_enter and
gdk_threads_leave.  The best thing to do with such ancient libraries is
not to use them.

Chris