void gtk_text_buffer_get_iter_at_offset ( GtkTextBuffer* buffer, GtkTextIter* iter, int char_offset )
iter to a position
char_offset chars from the start
of the entire buffer.
char_offset is -1 or greater than the number
of characters in the buffer,
iter is initialized to the end iterator,
the iterator one past the last valid character in the buffer.
Iterator to initialize.
The argument will be set by the function. The data is owned by the caller of the function.
Char offset from start of buffer, counting from 0, or -1