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See title.
I have:
class Foo { private: Foo(); public: static Foo* create(); } What need I do from here to make Foo un-copyable?
Thanks!
407
The typical way to make a C++ object non-copyable is to explicitly declare a copy constructor and copy-assignment operator but not implement them. This will prevent the compiler from generating its own.
class NonCopyable { public: NonCopyable (const NonCopyable &) = delete; NonCopyable & operator = (const NonCopyable &) = delete; protected: NonCopyable () = default; ~NonCopyable () = default; /// Protected non-virtual destructor }; class CantCopy : private NonCopyable {};
Boost::noncopyable prevents the classes methods from accidentally using the private copy constructor. Less code with boost::noncopyable.
In C++ copying the object means cloning. There is no any special cloning in the language. As the standard suggests, after copying you should have 2 identical copies of the same object.
class Foo { private: Foo(); Foo( const Foo& ); // non construction-copyable Foo& operator=( const Foo& ); // non copyable public: static Foo* create(); } If you're using boost, you can also inherit from noncopyable : http://www.boost.org/doc/libs/1_41_0/boost/noncopyable.hpp
EDIT: C++11 version if you have a compiler supporting this feature:
class Foo { private: Foo(); public: Foo( const Foo& ) = delete; // non construction-copyable Foo& operator=( const Foo& ) = delete; // non copyable static Foo* create(); } Note that deleted methods should be public: https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#Rc-delete
169
Make the copy constructor and the assignment operator private as well. Just the declaration is enough, you don't have to provide an implementation.
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