C++ objects serialization for Linux

Question

I'm doing a program that needs send and receive data over the network. I never dealt with object serialization. I readed about some recommendations about Boost and Google Protocol Buffers. For use in Linux which is the best?

If you know some other I will appreciate your help.

Thanks.

Answer 1

If you are transferring data over the network, I suggest using a binary form of serialization (not XML or similar). Qt offers classes for that, which allow you to pass any class known to Qt's meta system into a stream of data.

The problem is that C++ does not really support introspection as a language feature, so you'll have to know the data that is to be serialized.

In many cases a length indicator (use big-endian) followed by the data is a good way to serialize data.

Answer 2

I've used Boost.Serialization to serialize objects and transmit them over a socket. It's a very flexible library, objects can be serialized intrusively if you have access to them

class Foo
{
public:
    template<class Archive>
    void serialize(Archive& ar, const unsigned int version)
    {
        ar & _foo;
        ar & _bar;
    }

    int _foo;
    int _bar;
};

or non-intrusively if you don't have access to the object you need to serialize

namespace boost {
namespace serialization {

template<class Archive>
void serialize(Archive& ar, Foo& f, const unsigned int version)
{
    ar & f._foo;
    ar & f._bar;
}

} // namespace serialization
} // namespace boost

There are tricks to serialize Foo if it does not expose its members (_foo and _bar here), the documentation explains this quite well. To serialize Foo, you use an object in the boost::archive namespace: text, binary, or xml.

std::stringstream ss;
boost::archive::text_oarchive ar( ss );
Foo foo;
foo._foo = 1;
foo._bar = 2;
ar << foo;

reconstructing the archive into a Foo object is done like so

boost::archive::text_iarchive ar( ss );
Foo foo
ar >> foo;

Note this example is fairly trivial, and obviously when you introduce a network you'll be using sockets and buffers.