Set the width of a widget

["durandal neuf fr" <durandal neuf fr>]

Hello everybody,

I am new to GTK. I would like to set the width of a GtkFixed but I
haven't found in the doc how to do this.

This GtkFixed accepts drag-and-drop so I would like to restrict its
width to the width of what it contains, but it expands to the maximum
size it cans (it is in a HBox).

So is it possible to set the width of this widget, or a maximum width ?

Thanks,

durandal