#include "ns.h" extern int func(); // Note: the following function must be before the using. void test_lookup_before_using_directive() { // BP_before_using_directive std::printf("before using directive: func() = %d\n", func()); // eval func(), exp: 1 } using namespace A; void test_lookup_after_using_directive() { // BP_after_using_directive //printf("func() = %d\n", func()); // eval func(), exp: error, ambiguous std::printf("after using directive: func2() = %d\n", func2()); // eval func2(), exp: 3 std::printf("after using directive: ::func() = %d\n", ::func()); // eval ::func(), exp: 1 std::printf("after using directive: B::func() = %d\n", B::func()); // eval B::func(), exp: 4 }