How to pass a C++ short* to managed C# assembly in C++/CLI

Question

I'm having trouble passing an argument from C++/CLI code into a .NET C# function.

In C++ I have something resembling the following:

void SomeFunction(short *id)
{
   CSharpClass::StaticClassInstance->SetValue(id);
}

On the C# side, the function is declared with a ref argument as:

public void SetValue(ref short id)
{
  id = this.internalIdField;
}

The compiler error I'm getting when calling SetValue(id) is "cannot convert parameter 1 from 'short *' to 'short %'".

I found out that a tracking reference (%) is equivalent to C# ref but I don't know how to use it with the short* parameter I'm trying to pass.

Thanks in advance.

Answer 1

The logical C++/CLI signature of CSharpClass::SetValue is

void SetValue(short% id);

If you know C++ (as opposed to C++/CLI), the answer here is the exact same as it would be if you had the C++ signature

void SetValue(short& id);

I.e., simply dereference the pointer:

void SomeFunction(short *id)
{
    CSharpClass::StaticClassInstance->SetValue(*id);
}

Answer 2

If you want to be long winded, declare a tracking reference, assign the tracking reference to your id parameter and then pass the tracking reference to your function...

short %s = *id;

SetValue (s);

If you'd rather not be long winded, just dereference the pointer. While the compiler cannot convert a short * into a short % it can convert a short into a short %...

SetValue (*id);