Please Help again !!! Return statements and references in JNI !!!

Question

hi,
if somebody could help me again or have just a hint i am very thankful.
let us examine i have the following simple c/c++-code for rectangular integration:
JNIEXPORT void JNICALL
Java_ValueList_callg1(JNIEnv *env, jobject obj)
alpha[indx][temp]=-10*log10(integrate_rect(uk, ok, -aey/2., aey/2., sigmax, sigmay, 500, 500)this code calls the function integrate rect for a two dimensional rectangular integration and normally returns the double value temp to the function caller:
double integrate_rect(double rectxmin, double rectxmax, double rectymin, double rectymax, double sigmax, double sigmay, int xsteps, int ysteps)
     //cout<<"You are using trapezoid integration method !!!"<<endl;
     double xmin=trapxmin;
     double xmax=trapxmax;
     double ymin=trapymin;
     double ymax=trapymax;
     //declare number of trapezoids in x and y directions
     int m=xsteps;     //x direction
     int n=ysteps;     //y direction
     //declare steps in x and y directions
     double hx=(xmax-xmin)/m;
     double hy=(ymax-ymin)/n;
     double temp = 0.;
     double y=ymin;
               for (int indy = 0; indy < n; indy++)
                    {     //count y-steps
                         double x=xmin;
                                   for (int indx = 0; indx < m; indx++)
                                        {     //count x-steps
                                              /*add for every x,y loop the previous temp to the actual temp
                                               distance in x and y directions has to be added to every 'partial' function*/
                                               /**temp += (1./4.*hx*hy*(f(x, y, sigmax, sigmay) + f(x+hx, y, sigmax, sigmay) + f(x, y+hy, sigmax, sigmay) + f(x+hx, y+hy, sigmax, sigmay)));
                                               x+=hx;
                                        }     //end x direction
                                   y+=hy;
                    }     //end y direction
               return temp;     //return value to the function caller
}     //end of trapeziod integration     examine using JNI now: the integrate function returns type of double the JNI method "return" is void....so i do not want any value come back to java.
I want the value to reside in native code without passing the value outside native code and in again !!! Is this possible ???
Another question here is how to handle with references?? If i understand correct in JNI tutorial you have to create global references to prevent the "temp" value in integrate function beeing garbage collected.
I get stuck here because i did not find anything about multiple methods residing in native code.
e.g.
//rectangular integration
double integrate_rect(....)
return temp;
//integration through gsl library
double integrate_gsl(....)
return result:I want to return the result to the function caller on NOT to java.
Is it really the only solution to pass the value back to java and then to another native method again (which would result in multiple loops from java to native, to java and native back again....) or is there a trick how i can return a value to the function caller.
Please give me a hint on this.
regards

Answer 1

examine using JNI now: the integrate function returns
type of double the JNI method "return" is void....so
i do not want any value come back to java.
I want the value to reside in native code without
passing the value outside native code and in again
!!! Is this possible ???Yes. This is a C/C++ question however. The answer lies there - use a global variable.