C ++通过传递句柄减速器包装到C＃

Question

I have a function in c++ like this which has another function inside it like this:

Doom(int n, const array<double> ^x, int incx, int k, double r){
     pin_ptr<double> xptr = &(x[0]);
     fdoom(n, xptr, incx, &k, &r, &fail);
}

now when I call this function from c#:

int k = 0;
double r = 0.0;
CPPCode.Doom(n, x, incx,  k, r);

here my values k and r should change to 1 and -2 but this doesn't happen. So I have to use refrence for this to happenbut I am totally confused about how to use CLR reference for a single value.

note that the function fdoom is defined like this in it's class:

void    fdoom (Integer n, const double x[], Integer incx,
        Integer *k, double *r, NagError *fail) 

Answer 1

In managed C++ you should use % if you want to call it by reference from C#. That is your function look likes this:

Doom(int n, const array<double> ^x, int incx, int %k, double r){
     pin_ptr<double> xptr = &(x[0]);
     pin_ptr<int> kptr = &k;
     fdoom(n, xptr, incx, kptr, &r, &fail);
}

and in your C# function you should use ref keyword to call it by reference. That is:

CPPCode.Doom(n, x, incx, ref k, r);