gtk:notebook-tab-label-text (notebook child)

notebook -- a gtk:notebook widget
child -- a gtk:widget child contained in a page of the notebook
text -- a string with the label text

The gtk:notebook-tab-label-text function retrieves the text of the notebook tab label for the page containing child. The (setf gtk:notebook-tab-label-text) function creates a new label and sets it as the notebook tab label for the page containing child.