Re: [gtk-list] About multi threads

[Sebastian Wilhelmi <wilhelmi ira uka de>]

Hi, Jiang
> 
> I use gtk with multi-threads but met some problems:
> 
> if I use the "g_thread_init(NULL)" in the main() function, then the
> other thread function can not access the widget which is created in the
> main() function. But if I do not use g_thread_init(NULL), then
> everything is fine, all threads can access the widgets.
> 
> I wonder why?
> 
> Also, if I do not use g_thread_init(NULL), then there will be the
> problem of simultaneously accessing.
> 
> The following is a simple sample code.
> 
> 1. There is a thread function called:  "the_ui_thread()"
>      In that function, there is a loop which continuely recieve the
> message(simply a integer) from the server and then display it in an
> entry (which is a global widget and is created by create_window() in
> main())
> 
> 2.    In the main(), I will add more callback function (such as button
> clicked).
> 
> What I want to do is:
> 
> 1.  Both threads can access the widgets
> 2.  Each time, when a thread is running, only after it runs all the
> functions in it(fully completed),then it can change to the other thread.
> 
> I test many ways to do that, but all failed.
> 
> Any one can help me?? Please teach me ASAP
> 
> Thanks!!!!!

First of all, the test program is not standalone, and thus not very helpful.
on the other hand your problem seems to be here:

>      gdk_threads_enter();
> 
>      while(1)
>      {
>                msgrcv(msqid,&buf,sizeof(struct msgbuf),1,0);
>                sprintf(tempstring,"%d",buf.mtext);
>                gtk_entry_set_text(GTK_ENTRY(entry1),tempstring);
>                gtk_widget_show(window1);
>       }
> 
>     gdk_threads_leave();

Try instead something like:

      while(1)
      {
                msgrcv(msqid,&buf,sizeof(struct msgbuf),1,0);
                sprintf(tempstring,"%d",buf.mtext);
                gdk_threads_enter();
                gtk_entry_set_text(GTK_ENTRY(entry1),tempstring);
                gtk_widget_show(window1);
                gdk_threads_leave();
       }

your sample code locks out all other gtk calls during the while(1) loop, that
means effectivly forever.

Bye,
Sebastian
-- 
Sebastian Wilhelmi                   |            här ovanför alla molnen
mailto:wilhelmi@ira.uka.de           |      är himmlen så förunerligt blå
http://goethe.ira.uka.de/~wilhelmi   |