Russian Qt Forum

C++ (Qt)
class Base {
   Base() {}
   virtual ~Base() {}
};
 
class A : public Base {};
class B : public Base {};
//... и т.д.
 

C++ (Qt)
class Base {
   Base() {}
   virtual ~Base() = 0;
};
 
inline Base::~Base() {}
 

C++ (Qt)
QString s("text");
 

C++ (Qt)
#include <iostream>
class Base {
public:
        Base() {}
        virtual ~Base() = 0;
};
// inline ~Base() {}
 
class Derived: Base {
public:
        Derived() {};
        virtual ~Derived() {
                std::cout << "Derived::~Derived\n";
        }
};
 
int main() {
        Derived d;
        return 0;
}

alexander@goblin /tmp $ g++ 1.cpp
/tmp/cc3mCBWm.o: In function `Derived::~Derived()':
1.cpp:(.text._ZN7DerivedD2Ev[_ZN7DerivedD5Ev]+0x2f): undefined reference to `Base::~Base()'
1.cpp:(.text._ZN7DerivedD2Ev[_ZN7DerivedD5Ev]+0x58): undefined reference to `Base::~Base()'
collect2: выполнение ld завершилось с кодом возврата 1

C++ (Qt)
virtual ~Base() {}

C++ (Qt)
#include <iostream>
class Base {
public:
        Base() {}
        virtual ~Base() = 0;
};
 
inline Base::~Base() {}
 
class Derived: public Base {
public:
        Derived() {};
        virtual ~Derived() {}
};
 
int main() {
        int i=100500000;
        do {
                Derived d;
        } while(i--);
        return 0;
}
 

C++ (Qt)
#include <iostream>
class Base {
public:
        Base() {}
        virtual ~Base() {}
};
 
class Derived: public Base {
public:
        Derived() {};
        void foo() {};
        virtual ~Derived() {}
};
 
int main() {
        int i=100500000;
        do {
                Derived d;
        } while(i--);
        return 0;
}

alexander@goblin /tmp $ g++ 1.cpp -O0 -o test1
alexander@goblin /tmp $ g++ 2.cpp -O0 -o test2
alexander@goblin /tmp $ time ./test1

real    0m22.259s
user    0m22.254s
sys     0m0.001s
alexander@goblin /tmp $ time ./test1

real    0m22.286s
user    0m22.280s
sys     0m0.001s
alexander@goblin /tmp $ time ./test2

real    0m22.312s
user    0m22.263s
sys     0m0.034s
alexander@goblin /tmp $ time ./test2

real    0m22.270s
user    0m22.264s
sys     0m0.001s