The pImpl idiom in c++ aims to hide the implementation details (=private members) of a class from the users of that class. However it also hides some of the dependencies of that class which is usually regarded bad from a testing point of view. For example if class A hides its implementation details in Class AImpl which is only accessibl...
(Yes, I know that one machine instruction usually doesn't matter. I'm asking this question because I want to understand the pimpl idiom, and use it in the best possible way; and because sometimes I do care about one machine instruction.) In the sample code below, there are two classes, Thing and OtherThing. Users would include "thing....
Sometimes, C++'s notion of privacy just baffles me :-) class Foo { struct Bar; Bar* p; public: Bar* operator->() const { return p; } }; struct Foo::Bar { void baz() { std::cout << "inside baz\n"; } }; int main() { Foo::Bar b; // error: 'struct Foo::Bar' is private within this con...
Hi all, I recently switched back from Java and Ruby to C++, and much to my surprise I have to recompile files that use the public interface when I change the method signature of a private method, because also the private parts are in the .h file. I quickly came up with a solution that is, I guess, typical for a Java programmer: interfa...
I'm working on a library that defines a client interface for some service. Under the hood I have to validate the data provided by users and then pass it to "engine" process using Connection class from another library (note: the Connection class isn't known to the users of our library). One of my colleagues proposed using PIMPL: class Cl...
So I've been thinking about PIMPL and stack allocation. I've been writing a library and decided to use PIMPL to hide the private member of the class. That means I would have a class declared like this class Foo { private: class Handle; std::tr1::shared_ptr<Handle> handle; public: Foo(); }; It's pretty straight forward. But...
Consider the following: PImpl.hpp class Impl; class PImpl { Impl* pimpl; PImpl() : pimpl(new Impl) { } ~PImpl() { delete pimpl; } void DoSomething(); }; PImpl.cpp #include "PImpl.hpp" #include "Impl.hpp" void PImpl::DoSomething() { pimpl->DoSomething(); } Impl.hpp class Impl { int data; public: void DoSo...
This is a very noobish mistake, but I dont know whats happening here. There are loads of pimpl examples but I dont understand why this isn't working (this was one of the examples more or less but I dont see the difference). I have a very simple Pimpl example, but it wont work. // Foo.hpp #include <boost/scoped_ptr.hpp> class Foo { s...