Update label immediately

[Johannes Bauer <dfnsonfsduifb gmx de>]

Hello list,

I'm a gtkmm newbie, I started serious programming with it just days ago 
and am now far off the 5 kLOC border and already have impressive 
results. However, there is something that I cannot seem to get done:

I'm writing an application which reads from a DMM (asynchronously, I'm 
using pthreads - is that a bad idea?) and displays the gathered data 
graphically in a Gtk::DrawingArea and also updates the last value to a 
Gtk::Label. Events come in around every half second. The problem is, the 
label is not getting updated instantly, as I'd wish. Only when the mouse 
is moved over it, it apperas.

The code that modifies the label is simple:

label->set_label("foobar result");

So now what I played around with was:

label->get_window->process_updates(false);

Which is getting me a nasty

Xlib: unexpected async reply (sequence 0x363)!

I'm guessing process_updates is not reentrant and I have to take care 
about that myself. But - how?

Thanks in advance,
Johannes