#include <iostream>

using namespace std;

#define BOOST_SCOPE(name) \
if (const bool LABELED_SCOPE_##name = false){BOOST_BREAK(name); name##_end_scope:;} else


#define BOOST_BREAK(name) \
(void)LABELED_SCOPE_##name; goto name##_end_scope


int main()
{
    BOOST_SCOPE(a1)
    {
        BOOST_BREAK(a2);
        cout << "123\n";
    }
    return 0;
}