MIDL not allowing pointers?

Question

I am attempting create a C++ projection in C# using MIDL. According to this: https://learn.microsoft.com/en-us/windows/win32/rpc/reference-pointers MIDL allows pointers so in my .idl file I have defined as such:

namespace TestComponent {
    [default_interface]
    runtimeclass TestRuntimeClass {
        void TestFunction([in, out, ref] char *pChar);
    }
}

However, when this file compiles I get the error [msg] syntax error [context]: expecting an identifier near "*". Any ideas?