How to build log4cxx in Visual Studio 2015

Question

I have been using log4cxx, it worked OK for my needs. We are moving to VS 2015 and I have discovered that the compiler in Visual Studio 2015 is throwing errors when I try to rebuild log4cxx 0.10.0.1. The build still works if I change the project toolset to Visual Studio 2013 (v120), but when I try to use it has problems at runtime.
See below the error message it occurs on multiple occasions . Has anyone found a way to build log4cxx properly with Visual Studio 2015?

4>..\..\Log4cxx\log4cxx\apache-log4cxx-0.10.0\src\main\include\log4cxx/layout.h(90): error C2248: 'log4cxx::helpers::ObjectImpl::ObjectImpl': cannot access private member declared in class 'log4cxx::helpers::ObjectImpl'
4>..\..\Log4cxx\log4cxx\apache-log4cxx-0.10.0\src\main\include\log4cxx/helpers/objectimpl.h(43): note: see declaration of 'log4cxx::helpers::ObjectImpl::ObjectImpl'
4>..\..\SDKS\Log4cxx\log4cxx\apache-log4cxx-0.10.0\src\main\include\log4cxx/helpers/objectimpl.h(28): note: see declaration of 'log4cxx::helpers::ObjectImpl'
4>..\..\SDKS\Log4cxx\log4cxx\apache-log4cxx-0.10.0\src\main\include\log4cxx/layout.h(90): note: This diagnostic occurred in the compiler generated function 'log4cxx::Layout::Layout(const log4cxx::Layout &)'

score 3 · Accepted Answer · answered Jul 30 '15 at 12:20

I had the same problem and found a fix hopefully.

The problem is the definition of the base class ObjectImpl:

    class LOG4CXX_EXPORT ObjectImpl : public virtual Object
    {
    public:
        ObjectImpl();
        virtual ~ObjectImpl();
        void addRef() const;
        void releaseRef() const;

    protected:
        mutable unsigned int volatile ref;

    private:
        //
        //   prevent object copy and assignment
        //
        ObjectImpl(const ObjectImpl&);
        ObjectImpl& operator=(const ObjectImpl&);
    };

As you can see the class hides a copy constructor and the copy assignment operator, because the design using a reference counter has no suitable implementation. It would have been better to use shared pointers.

The new stl implementation uses the move semantic for their collection classes and when there is no copy constructor and copy assignment operator with move semantic it has to use the standard operators, which are not available.

To solve this problem, we have to add the move operators to the following classes: ObjectImpl, Layout, Filter, PatternConverter, TriggeringPolicy and RollingPolicyBase.

Here is my new implementation for ObjectImpl:

    class LOG4CXX_EXPORT ObjectImpl : public virtual Object
    {
    public:
        ObjectImpl();
        virtual ~ObjectImpl();
        void addRef() const;
        void releaseRef() const;

        // added for VS2015
        ObjectImpl(ObjectImpl && o)
        {
            ref = o.ref;
            o.ref = 0;
        }

        ObjectImpl& operator=(ObjectImpl && o)
        {
            ref = o.ref;
            o.ref = 0;

            return *this;
        }
        // -----

    protected:
        mutable unsigned int volatile ref;

    private:
        //
        //   prevent object copy and assignment
        //
        ObjectImpl(const ObjectImpl&);
        ObjectImpl& operator=(const ObjectImpl&);
    };

And one other example. The remaining classes are similar:

    class LOG4CXX_EXPORT Filter : public virtual OptionHandler,
        public virtual helpers::ObjectImpl
    {
        /**
        Points to the next filter in the filter chain.
        */
        FilterPtr next;
    public:
        Filter();

        // added for VS2015
        Filter(Filter && o)
            : helpers::ObjectImpl(std::move(o))
            , next( o.next )
        { }

        Filter& operator=(Filter && o)
        {
            helpers::ObjectImpl::operator=(std::move(o));
            next = o.next;
            return *this;
        }
        // end of added for VS2015

        ...

I hope that helps.

Thanks Dirk. Very good explanation and It all works for me very well now. — Nik, Jul 30 '15 at 16:25
Might not be instantly obvious, but you will need to add default constructor for (Layout, TriggeringPolicy). Also in PatternConverter, const specifier should be removed from fields name and style, otherwise assignment operator will not compile. — Peter, Oct 06 '15 at 14:45
@Nik Can you please post the changes in other classes that you have made? — Neeraj, Apr 19 '16 at 07:00

score 1 · Answer 2 · answered Sep 23 '16 at 22:27

1

A coworker had this problem and he solved it by going to File > New > Project > Visual C++ and choosing Install Windows XP Support for C++. Strangely, I have never done that and yet I also never had the same problem.

answered Sep 23 '16 at 22:27

snips-n-snails

637
5
22

score 0 · Answer 3 · edited Dec 07 '21 at 08:47

The following code is the right answer apache-log4cxx-0.10.0 vs2015

// objectimpl.h
namespace log4cxx
{
   namespace helpers
   {
      /** Implementation class for Object.*/
      class LOG4CXX_EXPORT ObjectImpl : public virtual Object
      {
      public:
         ObjectImpl();
         virtual ~ObjectImpl();
         void addRef() const;
         void releaseRef() const;

      protected:
         mutable unsigned int volatile ref;

        //private:
                        //
            //   prevent object copy and assignment
            //
        ObjectImpl(const ObjectImpl&);
        ObjectImpl& operator=(const ObjectImpl&);
      };
   }
}

// objectimpl.cpp
ObjectImpl::ObjectImpl(const ObjectImpl& o)
{
    ref = o.ref;
    o.ref = 0;
}
ObjectImpl& ObjectImpl::operator=(const ObjectImpl& o)
{
    ref = o.ref;
    o.ref = 0;

    return *this;
}

How to build log4cxx in Visual Studio 2015

3 Answers3