Implements non-standard C++ friend declaration behavior that allows friend declarations to be visible in the enclosing scope.
#pragma old_friend_lookup on | off | reset
This example shows friend declarations that are invalid without #pragma old_friend_lookup.
class C2;
void f2();
struct S {
friend class C1;
friend class C2;
friend void f1();
friend void f2();
};
C1 *cp1; // error, C1 is not visible without namespace declaration
C2 *cp2; // OK
int main()
{
f1(); // error, f1() is not visible without namespace declaration
f2(); // OK
}