下面使用 mpl::list 来初始化一个 boost 变体。然后它序列化变体。它在保存但不加载时编译并正常工作。编译甚至加载失败。有谁知道问题是什么？谢谢
属性.h
#include <string>
#include <boost/archive/xml_oarchive.hpp>
#include <boost/archive/xml_iarchive.hpp>
template <class T>
class Attribute
{
public:
Attribute() {}
Attribute( const std::string& name, const T& t ) : name_( name ), t_( t ) {}
std::string name() const { return name_; }
const T& get() const { return t_; }
void set( const T& t ) { t_ = t; }
friend class boost::serialization::access;
template<class Archive>
void serialize( Archive& ar, const unsigned int version )
{
ar & BOOST_SERIALIZATION_NVP( name_ );
ar & BOOST_SERIALIZATION_NVP( t_ );
}
private:
std::string name_;
T t_;
};
AttributeAny.h
#include <boost/variant.hpp>
#include <boost/archive/xml_oarchive.hpp>
#include <boost/archive/xml_iarchive.hpp>
#include <boost/variant/apply_visitor.hpp>
template <class T>
class AttributeAny
{
public:
typedef typename boost::make_variant_over<T>::type Type;
AttributeAny() {}
AttributeAny( const Type& t ) : t_( t ) { }
private:
template <class Archive>
class SerializeVisitor : public boost::static_visitor<>
{
public:
SerializeVisitor( Archive& ar ) : ar_( ar ) {}
template <typename U>
void operator()( const U& t ) const
{
ar_ & BOOST_SERIALIZATION_NVP( t );
}
private:
Archive& ar_;
};
public:
friend class boost::serialization::access;
template<class Archive>
void serialize( Archive& ar, const unsigned int version )
{
boost::apply_visitor( SerializeVisitor<Archive>( ar ), t_ );
}
private:
Type t_;
};
主文件
#include <iostream>
#include <sstream>
#include <boost/mpl/list.hpp>
#include <boost/archive/xml_oarchive.hpp>
#include <boost/archive/xml_iarchive.hpp>
#include <boost/serialization/shared_ptr.hpp>
#include "mylib/Attribute.h"
#include "mylib/AttributeAny.h"
using namespace std;
class A
{
public:
A() {}
A( const std::string& name ) : name_( name ) {}
std::string name() const { return name_; }
friend class boost::serialization::access;
template<class Archive>
void serialize( Archive& ar, const unsigned int version )
{
ar & BOOST_SERIALIZATION_NVP( name_ );
}
private:
std::string name_;
};
using namespace std;
typedef AttributeAny<boost::mpl::list<
// Attribute<double>
// , Attribute<long>
A // this, doesn't even work, on serialize load
> > Any;
int main()
{
A a( "a" );
Any any( a );
Any any1( a );
std::stringstream ss;
boost::archive::xml_oarchive oa( ss );
oa << BOOST_SERIALIZATION_NVP( a );
cout << ss.str() << endl;
// these 2 lines below cause compilation error
// serialize save work just fine...
boost::archive::xml_iarchive ia( ss );
ia >> BOOST_SERIALIZATION_NVP( any1 );
return 0;
}
编译错误：
/usr/local/boost/boost_1_48_0/include/boost/archive/detail/check.hpp: In function ‘void boost::archive::detail::check_const_loading() [with T = const A]’:
/usr/local/boost/boost_1_48_0/include/boost/archive/detail/iserializer.hpp:577: instantiated from ‘void boost::archive::load(Archive&, T&) [with Archive = boost::archive::xml_iarchive, T = const A]’
/usr/local/boost/boost_1_48_0/include/boost/archive/detail/common_iarchive.hpp:66: instantiated from ‘void boost::archive::detail::common_iarchive<Archive>::load_override(T&, int) [with T = const A, Archive = boost::archive::xml_iarchive]’
/usr/local/boost/boost_1_48_0/include/boost/archive/basic_xml_iarchive.hpp:86: instantiated from ‘void boost::archive::basic_xml_iarchive<Archive>::load_override(const boost::serialization::nvp<T>&, int) [with T = const A, Archive = boost::archive::xml_iarchive]’
/usr/local/boost/boost_1_48_0/include/boost/archive/xml_iarchive.hpp:93: instantiated from ‘void boost::archive::xml_iarchive_impl<Archive>::load_override(T&, int) [with T = const boost::serialization::nvp<const A>, Archive = boost::archive::xml_iarchive]’
/usr/local/boost/boost_1_48_0/include/boost/archive/detail/interface_iarchive.hpp:60: instantiated from ‘Archive& boost::archive::detail::interface_iarchive<Archive>::operator>>(T&) [with T = const boost::serialization::nvp<const A>, Archive = boost::archive::xml_iarchive]’
/usr/local/boost/boost_1_48_0/include/boost/archive/detail/interface_iarchive.hpp:67: instantiated from ‘Archive& boost::archive::detail::interface_iarchive<Archive>::operator&(T&) [with T = const boost::serialization::nvp<const A>, Archive = boost::archive::xml_iarchive]’
~/ws/mylib/AttributeAny.h:34: instantiated from ‘void AttributeAny<T>::SerializeVisitor<Archive>::operator()(const U&) const [with U = A, Archive = boost::archive::xml_iarchive, T = boost::mpl::list<A, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na>]’
/usr/local/boost/boost_1_48_0/include/boost/variant/variant.hpp:858: instantiated from ‘typename Visitor::result_type boost::detail::variant::invoke_visitor<Visitor>::internal_visit(T&, int) [with T = A, Visitor = const AttributeAny<boost::mpl::list<A, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> >::SerializeVisitor<boost::archive::xml_iarchive>]’
...
../src/test_mylib.cpp:61: instantiated from here
/usr/local/boost/boost_1_48_0/include/boost/archive/detail/check.hpp:162: error: invalid application of ‘sizeof’ to incomplete type ‘boost::STATIC_ASSERTION_FAILURE<false>‘
/usr/local/boost/boost_1_48_0/include/boost/archive/detail/check.hpp:162: error: invalid application of ‘sizeof’ to incomplete type ‘boost::STATIC_ASSERTION_FAILURE<false>‘
make: *** [src/test_mylib.o] Error 1