I know that the C++/CLI code
void foo(Bar^% x);
transforms into
Void foo(ref Bar x);
What is the C++/CLI cod
There is no such specific syntax in C++/CLI. I think you can get fairly close by adding the OutAttribute to modify the parameter. But I'm not sure that achieves the exact same semantics as C# out.
The concept of out is for the most part limited to C#. The CLR really only sees ref parameters. The out concepts is achieved via a mod opt I believe and most languages ignore it.
You can use the OutAttribute:
using namespace System::Runtime::InteropServices;
void foo([Out] Bar^% x);