GtkTextBuffer:Compare text with those from GtkEntry

[xiangbing <xb_parasite tom com>]

Hi,
I try to write a program to test typing speed.I decide to use a GtkEntry wiget to get the input .The text in GtkTextBuffer is presetted and is shown in a GtkTextView wiget.If user's input is the same to the text in GtkTextBuffer,those text will be underlined.

My trouble is I don't know how to compare the text encoding in UTF-8 format.I wonder if there are some documents about gtkUTF-8 somewhere .Or if anyone can give me a brief hints ,that makes good ,too .

Thanks,
  xiangbing