fontmap = pfont:GetFontMap()
Note that the font maintains a *weak* reference to
the font map, so if all references to font map are
dropped, the font map will be finalized even if there
are fonts created with the font map that are still alive.
In that case this function will return a NULL object.
It is the responsibility of the user to ensure that the font map is kept alive. In most uses this is not an issue as a Pango context holds a reference to the font map.
You mustn't free the returned font map.