use gchar as gtk_text_buffer: possible?

[Rudra Banerjee <rudra banerjee aol co uk>]

Can I have something like this?
        in main.h
        char* buffer;
         
        void in_program(){
        gtk_text_buffer_set_modified (GTK_TEXT_BUFFER(buffer), TRUE);
        }

I have defined buffer to have g_file_get_contents easily.
So, any way to use gchar as gtk_text_buffer?