A GtkTextMark is like a bookmark in a text buffer; it preserves a position in the text. You can convert the mark to an Gtk.TextIter iterator using TextBuffer.GetIterAtMark(TextMark). Unlike iterators, marks remain valid across buffer mutations, because their behavior is defined when text is inserted or deleted. When text containing a mark is deleted, the mark remains in the position originally occupied by the deleted text. When text is inserted at a mark, a mark with left gravity will be moved to the beginning of the newly-inserted text, and a mark with right gravity will be moved to the end.

Marks optionally have names; these can be convenient to avoid passing the Gtk.TextMark object around.

Marks are typically created using the TextMark.CreateMark(TextMark) function.