//: C01:Wrapped.cpp // Safe, atomic pointers. #include <iostream> #include <cstddef> using namespace std; // Simplified. Yours may have other arguments. template<class T, int sz = 1> class PWrap { T* ptr; public: class RangeError {}; // Exception class PWrap() { ptr = new T[sz]; cout << "PWrap constructor" << endl; } ~PWrap() { delete[] ptr; cout << "PWrap destructor" << endl; } T& operator[](int i) throw(RangeError) { if(i >= 0 && i < sz) return ptr[i]; throw RangeError(); } }; class Cat { public: Cat() { cout << "Cat()" << endl; } ~Cat() { cout << "~Cat()" << endl; } void g() {} }; class Dog { public: void* operator new[](size_t) { cout << "Allocating a Dog" << endl; throw 47; } void operator delete[](void* p) { cout << "Deallocating a Dog" << endl; ::operator delete[](p); } }; class UseResources { PWrap<Cat, 3> cats; PWrap<Dog> dog; public: UseResources() { cout << "UseResources()" << endl; } ~UseResources() { cout << "~UseResources()" << endl; } void f() { cats[1].g(); } }; int main() { try { UseResources ur; } catch(int) { cout << "inside handler" << endl; } catch(...) { cout << "inside catch(...)" << endl; } } ///:~
Listado 2.9. C01/Wrapped.cpp
Cat() Cat() Cat() PWrap constructor allocating a Dog ~Cat() ~Cat() ~Cat() PWrap destructor inside handler