Calling Eclipse functions from C++

Hello,
I don't know if I am missing anything or what is happening with my
program.
I am programming in C++ and I need to call Eclipse 5.8.

I have implemented a predicate for Eclipse to solve one problem and I
need to call it from C++.
The file where I have the predicate is called CLP_predicates and I save
it as ".pl" and ".ecl", which extension I have to use? I get an error
when I try to compile it from C++.
The code I am using to compile it is:

		ec_init();
		post_goal("compile(CLP_predicates)");
		EC_resume();

And the error I get is:

 "Instantiation fault in compile(CLP_predicates) in module eclipse"

And another question is: In the section 3.4 of the "Embedding and
Interfacing Manual" says that the ec_xt_double_arr is a predefined
method table for arrays of doubles. How could I use it? Do I have to
compile any other file? I can not compile my C++ program because I get
this error:
 
"error C2065: 'ec_xt_double_arr' : undeclared identifier"


I think I am following the explanations of that manual mentioned before
and the answers of my past mails.

Thank you very much,

Roman Buil