copy-constructor

From the boost library documentation I read this: Conceptually, smart pointers are seen as owning the object pointed to, and thus responsible for deletion of the object when it is no longer needed. I have a very simple problem: I want to use RAII for pointer attributes of a class that is Copyable and Assignable. The copy and assignment operations should be deep: every object should have its own copy of the actual data. Also, RTTI needs to be available for the attributes (their type may also be determined at runtime). Should I be searching for an implementation of a Copyable smart pointer (the

I was reading the difference between direct-initialization and copy-initialization (§8.5/12): T x(a); //direct-initialization T y = a; //copy-initialization What I understand from reading about copy-initialization is that it needs accessible & non-explicit copy-constructor , or else the program wouldn't compile. I verified it by writing the following code: struct A { int i; A(int i) : i(i) { std::cout << " A(int i)" << std::endl; } private: A(const A &a) { std::cout << " A(const A &)" << std::endl; } }; int main() { A a = 10; //error - copy-ctor is private! } GCC gives an error ( ideone )

As far as I know, the copy constructor must be of the form T(const T&) or T(T&) . What if I wanted to add default arguments to the signature? T(const T&, double f = 1.0); Would that be standards compliant? Yes. §[class.copy]/2: A non-template constructor for class X is a copy constructor if its first parameter is of type X& , const X& , volatile X& or const volatile X& , and either there are no other parameters or else all other parameters have default arguments [ Example: X::X(const X&) and X::X(X&,int=1) are copy constructors. You can just create two different constructors: T(const T&) T

Consider the following C++ code: struct B { }; struct A { A(int); A(A&); // missing const is intentional A(B); operator B(); }; A f() { // return A(1); // compiles fine return 1; // doesn't compile } This compiles fine on MSVC++ 2010 (in fact, on MSVC it even works if I remove B altogether). It doesn't on GCC 4.6.0: conv.cpp: In function ‘A f()’: conv.cpp:13:9: error: no matching function for call to ‘A::A(A)’ conv.cpp:13:9: note: candidates are: conv.cpp:6:2: note: A::A(B) conv.cpp:6:2: note: no known conversion for argument 1 from ‘A’ to ‘B’ conv.cpp:5:2: note: A::A(A&) conv.cpp:5:2: note: