thanks! but as for assigning b_dot i did already use the function exactely as you said:

p.bmap=bmapCheck(b_dot, b_dot_file);

but this does not work. using the BMAP** and *source idea did only lead to engine crashes and doesnt really work. (i did call it with b_dot=bmapCheck(&b_dot, b_dot_file); in this case)