#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include "ppport.h"

static SV * userfunc;

double userfunc_wrapper(double *x) {
    int n;
    double r;
    
    dSP;
    ENTER;
    SAVETMPS;

    PUSHMARK(SP);
    XPUSHs(sv_2mortal(newSVnv(*x)));
    PUTBACK;

    n = call_sv(userfunc, G_SCALAR);

    SPAGAIN;
    if (n != 1) croak("wrong number of args returned!\n");
    r = POPn;
    
    PUTBACK;
    FREETMPS;
    LEAVE;
    return r;
}

// the Fortran function
double myfunc_(double *x, double *y, void* func);


double myfunc(double x, double y) {
    double r;
    r = myfunc_(&x, &y, &userfunc_wrapper);
    return r;
}


MODULE = P2f2p		PACKAGE = P2f2p		

double
myfunc(x, y, ufunc)
        double x
        double y
        SV * ufunc
    CODE:
        userfunc = newSVsv(ufunc);
        RETVAL = myfunc(x, y);
    OUTPUT:
        RETVAL