Re: Multi-threaded GUI

[Michael L Torrie <torriem chem byu edu>]

On Wed, 2006-10-04 at 23:34 -0400, Melvin Newman wrote:
> My saga towards updating the GUI continues... the following are two
> code snippets:

While Paul explained why the code does not compile, I did a quick google
search and found this e-mail exchange which talks about how to do the
same things as g_idle_add but with within the framework of GtkMM.  This
will likely help you figure out how to set a non-static class member as
a callback:

http://www.nabble.com/Threading-Problem-t2341133.html

Specifically, perhaps this will work:

http://www.gtkmm.org/docs/glibmm-2.4/docs/reference/html/classGlib_1_1SignalIdle.html

Signal handlers in Gtkmm are allowed to be non-static class members so
maybe this would work for you.

Michael



> 
> 1) My window update function. It is built into the window1 class and
> is supposed to update the main GUI window:
> 
> gboolean window1::updater(gpointer data) 
> {
>     /* Variables
>     ******************************************/
>         Glib::RefPtr<Gdk::Window>win = get_window();
>     /*****************************************/
>     
>     if(win)
>     { 
>         Gdk::Rectangle r(0, 0, get_allocation().get_width
> (),get_allocation().get_height());
>         win->invalidate_rect(r, false);
>     }
>     return(true);
> }
> 
> 
> 2) The following is my thread that calls this function through the
> g_idle_add() function... Unfortunately it does not compile at this
> line and being new to OO/C++ I have no idea why, or how to fix the
> problem: 
> 
> void *server_connect(void *ptr)
> {
>     /* Variables
>     ******************************************/
>         int tmp=0;
>         int socket_id;
>         struct sockaddr_in address;
>         gpointer data; 
>         Glib::RefPtr<Gtk::TextBuffer> buffer;
>         sigc::connection pipe1;
>     /*****************************************/
>     
>     socket_id = pthread_arg.socket_id;
>     address = pthread_arg.address; 
>     buffer = pthread_arg.out_put_buffer;
>         
>     do
>     {
>         tmp = connect (socket_id,(struct sockaddr *) &address, sizeof
> (struct sockaddr));
>         if (tmp <0)
>         {
>             buffer->insert_at_cursor("@"); 
>             
>             g_idle_add(window1::updater,false); 
>                ^-- Compiling stops here with: error: invalid use of
> non-static member function `gboolean window1::updater(void*)'
>             
>             Glib::usleep(400000);
>         }
>         
>     }while(tmp<0);
>     
> }
> 
> Unfortunately I cant seem to integrate the server_connect function
> into the class, because pthread then complains that it can not call it
> (miss mach type). 
> 
> Any help would be greatly appreciated.
> 
> Sincerely
> Melvin Newman
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