Gtk::ProgressBar doesn't work synchronously

["Garth's KidStuff" <garthskidstuff gmail com>]

Hi All,

I'm converting a large Windows/Mac project to run on Ubuntu, and I'm a
little stuck when trying to use a ProgressBar.  We have a cross-platform
class that assumes I can create a "Progress Monitor" dialog during
time-intensive tasks, and then periodically update the progress as the task
completes.

The problem that I'm having with using Gtk::ProgressBar seems to be a
fundemental one about when dialogs can actually appear in the main window.
For example, what I'd like to do is something along the lines of:

[in my main thread]
...
Start a complex task
Create a Progress Monitor dialog and show it
Update the dialog as the task progresses
Destroy the dialog
....

When I try this, nothing shows up *grin*.  As far as I can tell, I need to
let the run loop process so that the dialog can be shown. (i.e. if I omit
the "destroy" step in the above, I see the dialog as soon as I drop out of
"my" code in the main thread, but that's too late -- the task is already
completed)

One way to solve this is, of course, to rewrite all the places that use the
Progress Monitor so that the work is done in a thread and the main thread
can just be showing the progress bar.  I'd hesitate to try that with this
code base because of the number of places in cross-platform code that would
have to be rewritten.

Do any of you have any thoughts?

Thanks in advance!

-- 
Garth Upshaw
Garth's KidStuff