How call RAW text with Prolog predicate from C?

Hello. I'am sorry for my bad English(russian).

I want call from C application Prolog predicates. 
I try that:

PlTerm goal;
....
Pl_Start_Prolog(0, 0);

char str[]="asserta(parent(bob,mary))"; //or ANYthing else in string
format.

goal = Pl_Mk_Atom(Pl_Create_Allocate_Atom(str));

args = Pl_Rd_Callable_Check(goal, &functor, &arity);

Pl_Query_Begin(PL_TRUE);

Pl_Query_Call(functor, arity, args);

Pl_Query_End(PL_KEEP_FOR_PROLOG);



Pl_Stop_Prolog();

But that not work.
Please help me.