Sets @iter to the currently selected node if @selection is set to
#GTK_SELECTION_SINGLE or #GTK_SELECTION_BROWSE. @iter may be NULL if you
just want to test if @selection has any selected nodes. @model is filled
with the current model as a convenience. This function will not work if you
use @selection is #GTK_SELECTION_MULTIPLE.
Sets @iter to the currently selected node if @selection is set to #GTK_SELECTION_SINGLE or #GTK_SELECTION_BROWSE. @iter may be NULL if you just want to test if @selection has any selected nodes. @model is filled with the current model as a convenience. This function will not work if you use @selection is #GTK_SELECTION_MULTIPLE.