Compiler Error C2786

  • Article

'type' : invalid operand for __uuidof

The __uuidof operator takes a user-defined type with a GUID attached or an object of such a user-defined type. Possible causes:

  1. The argument is not a user-defined type.

  2. __uuidof cannot extract the GUID from the argument.

The following sample generates C2786:

// C2786.cpp
struct __declspec(uuid("00000000-0000-0000-0000-000000000000")) A {};

int main() {
   __uuidof(int);   // C2786
   __uuidof(int *);   // C2786
   __uuidof(A **);   // C2786

   // no error
   __uuidof(A);
   __uuidof(A *);
   __uuidof(A &);
   __uuidof(A[]);

   int i;
   int *pi;
   A **ppa;

   __uuidof(i);      // C2786
   __uuidof(pi);     // C2786
   __uuidof(ppa);    // C2786
}