#include <string>
 
class Base {
public:
    Base(void) {}
    virtual ~Base(void) throw() {}
};
 
class Derived : public Base {
public:
    ::std::string s;
};
 
int main(int, char**)
{
    return 0;
}

g++ test.cpp
test.cpp:9: error: looser throw specifier for ‘virtual Derived::~Derived()’
test.cpp:6: error:   overriding ‘virtual Base::~Base() throw ()’