Returns the text in the specified range (start, end). This method does not return characters representing embedded images, so byte and character indexes into the returned string do not correspond to byte and character indexes into the buffer. Text marked with tags that set the invisibility attribute are excluded if include_hidden_chars is FALSE.
Note: If you want to get the full text stored in the GtkTextBuffer, use the get_start_iter() and get_end_iter() respectively.
See also: set_text()