File Selection Dialog filter

["Kevin E.Gilbert" <gilbert bluemarble net>]

I am porting my openMotif code to gtk and I need a file selection dialog
with options for the user to chose the type of file to be read and also to
filter files by extension. This is pretty standard stuff in Windows and
Motif but I can't find an example with gtk. Has anyone published such a
widget or a method for extending the standard file selection dialog to do
this? We read over 20 different file formats and write nearly that many.

Kevin Gilbert
Serena Software