It seems like there must be a duplicate question, but I haven't been able to find it.
I'm writing a bridge to let an old C program access some C# objects. The bridge is written in C++/CLI.
In one case there is a C# function that's defined as:
public static string GetNameAndValue(out int value);
My C++/CLI wrapper function:
char* GetNameAndValue(int* value);
Which is easy enough to call from C. But how do I call the C# method from C++/CLI?
I first tried the obvious:
String ^ str;
str = TheObject::GetNameAndValue(value);
That gives me error C2664: Cannot convert parameter 2 from 'int *' to 'int %'.
Okay, then, how about GetNameAndValue(%value)? That gives me error C3071: operator '%' can only be applied to an instance of a ref class or a value-type.
Fair enough. So if I create an int I can pass it with %??
int foo;
str = TheObject::GetNameAndValue(%ix);
No dice. C3071 again. Which I find odd because int definitely is a value-type. Or is it?
There must be some magic combination of %, ^, &, or some other obscenity that will do what I want, but after swearing at this thing for 30 minutes I'm stumped. And searching Google for different combinations of C++/CLI and C# mostly gives information about how to call C++ from C#.
SO, my question: How do you pass an int from C++/CLI to a C# method that expects an out int (or ref int, if I have to)?
C#:
class MyClass
{
public static string GetNameAndValue(out int value);
}
C++/CLI:
int value;
String^ x = MyClass::GetNameAndValue(value);
C++/CLI wrapper:
CString GetNameAndValue(int* value)
{
String^ x = MyClass::GetNameAndValue(*value);
return CString(x);
}
C++/CLI wrapper 2:
CString GetNameAndValue(int& value)
{
String^ x = MyClass::GetNameAndValue(value);
return CString(x);
}
It's the same for C# "ref".
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