Re: Threads and gtkmm

[Chris Vine <chris cvine freeserve co uk>]

On Tue, 29 Mar 2011 11:42:56 +0200
Yann Leydier <yann leydier info> wrote:
> Thanks for the info. I was still using g_idle_connect with static 
> methods to communicate between threads…

I assume you mean g_idle_add(), and that's a perfectly good way to do
it, and is thread safe, but you forfeit trackability.  (Although if you
are passing static class member functions to the callback argument of
g_idle_add() you technically have undefined behaviour because static
member functions have C++ linkage specification and not C linkage.
However, it will work OK with gcc, and glibmm does it, so you are not
adding any greater unportability.)
 
> I have a question on how to transmit the dispatcher to an object. The 
> documentation seems to indicate that the default copy constructor and 
> operator are used. Does this mean that I can send my dispatcher
> object to other objects directly ?
> MyClass
> {
> 	public:
> 		MyClass(const Glib::Dispatcher &d):
> 			dispatcher(d)
> 		{ }
> 	private:
> 		Glib::Dispatcher dispatcher;
> { }
>
> Or shall I use a pointer (or a reference) (that can be dangerous 
> depending on the destruction order of the objects) ?
> MyClass
> {
> 	public:
> 		MyClass(Glib::Dispatcher *d):
> 			dispatcher(d)
> 		{ }
> 	private:
> 		Glib::Dispatcher *dispatcher;
> }

The first won't work because Dispatchers can't be copied (this is a
feature not a bug).  The second is not desirable because passing around
Dispatchers by pointer is likely to leave your code with dangling
pointers.

If a Dispatcher is a class member, why not provide an accessor
function, or make it a public member?  These would be the normal ways of
doing it (as with sigc::signal objects).

Chris