Deal with height and width

[Guillaume Ontabilla <guillaume ontabilla flying-robots com>]

Hello all,

I'm starting to use Gtkmm and I'm searching to manage height and with of
different widget, like Gtk::HBox for example.

The set_size_request() member function, only work for minimum value and
I need to set up maximum value too.

I've tried to use set_allocation(), but this member function is
protected :(

Is anyone can help me ?

Best regards.