text view, text buffer, text iter problems

[stanks <stanks gmx net>]

Hi

I am trying to get text buffer so i can save it to disk. I have found a 
few examples about that, but i get NULL every time when i call 
gtk_text_buffer_get_text.

My example:
Opening file:
I call gtk_text_view_new then gtk_text_view_get_buffer and i save handle 
i receive from gtk_text_view_get_buffer. When i call g_locale_to_utf8 
and after that gtk_text_buffer_set_text everything is ok...i see opened 
text file. This is everything ok.

Saving file (problem):
Call for gtk_text_buffer_get_iter_at_offset so i get start iter and then 
again gtk_text_buffer_get_iter_at_offset for end iter. After that 
gtk_text_buffer_get_text with already saved text buffer handle and here 
i get NULL.
I don't know what i am doing wrong :(
And i need to know all members of structure GtkTextIter....maybe this is 
problem. I didn't give you any code because i am doing my program in asm 
not in C.
I notice under debugger when i call gtk_text_buffer_get_iter_at_offset 
structure GtlTextIter (that i declared without members) is filled with 
12 or 13 dword's!
So the main problem is with getting text from buffer and structure 
gtk_text_buffer_get_iter_at_offset.
Well this is for now.

Thanks in advance

stanks