gtk-text-buffer-insert-markup (buffer iter markup)

buffer -- a gtk-text-buffer object
iter -- a gtk-text-iter iterator with a position in the text buffer
markup -- a UTF-8 string containing Pango markup

Inserts the text in markup at the position of the iterator. The text in markup will be inserted in its entirety and must be valid UTF-8. Emits the "insert-text" signal, possibly multiple times. Insertion actually occurs in the default handler for the signal. The iterator will point to the end of the inserted text on return.