Engine structure

When all required databases are loaded you should prepare the detection engine by calling cl_build. In the case of failure you should free the memory occupied by the engine with cl_free:

	int cl_build(struct cl_engine *engine);
	void cl_free(struct cl_engine *engine);

In our example:

	if((ret = cl_build(engine))) {
	    printf("cl_build() error: %s\n", cl_strerror(ret));
	    cl_free(engine);
	    exit(1);
	}