Question

I am serializing the cl_long2 type from OpenCL which is defined like this (simplified from /usr/include/CL/cl_platform.hpp):

typedef int64_t cl_long;
typedef union
{
    cl_long __attribute__ ((aligned(16))) s[2];
    struct{ cl_long  x, y; };
    struct{ cl_long  s0, s1; };
    struct{ cl_long  lo, hi; };
} cl_long2;

I defined the following stand-alone serialization function:

namespace boost{ namespace serialization {
template<class Archive> void serialize(Archive &ar, cl_long2 &i, const unsigned version){
   ar & make_nvp("x",i.x);
   ar & make_nvp("y",i.y);
}

}};

When I compile my code, which invokes a serialization of cl_long2 from as a class member, I am getting the following error, which I cannot understand (the error is the same if it is not a std::vector<cl_long2>, just a stand-alone variable):

/usr/include/boost/archive/detail/check.hpp: In function ‘void boost::archive::detail::check_object_level() [with T = cl_long2]’:
/usr/include/boost/archive/detail/iserializer.hpp:438:9:   instantiated from ‘static void boost::archive::detail::load_non_pointer_type<Archive>::invoke(Archive&, T&) [with T = cl_long2, Archive = boost::archive::xml_iarchive]’
/usr/include/boost/archive/detail/iserializer.hpp:592:5:   instantiated from ‘void boost::archive::load(Archive&, T&) [with Archive = boost::archive::xml_iarchive, T = cl_long2]’
/usr/include/boost/archive/detail/common_iarchive.hpp:66:9:   instantiated from ‘void boost::archive::detail::common_iarchive<Archive>::load_override(T&, int) [with T = cl_long2, Archive = boost::archive::xml_iarchive]’
/usr/include/boost/archive/basic_xml_iarchive.hpp:86:9:   instantiated from ‘void boost::archive::basic_xml_iarchive<Archive>::load_override(const boost::serialization::nvp<T>&, int) [with T = cl_long2, Archive = boost::archive::xml_iarchive]’
/usr/include/boost/archive/xml_iarchive.hpp:93:9:   instantiated from ‘void boost::archive::xml_iarchive_impl<Archive>::load_override(T&, int) [with T = const boost::serialization::nvp<cl_long2>, Archive = boost::archive::xml_iarchive]’
/usr/include/boost/archive/detail/interface_iarchive.hpp:60:9:   [ skipping 5 instantiation contexts ]
/usr/include/boost/serialization/split_free.hpp:58:9:   instantiated from ‘static void boost::serialization::free_loader<Archive, T>::invoke(Archive&, T&, unsigned int) [with Archive = boost::archive::xml_iarchive, T = std::vector<cl_long2>]’
/usr/include/boost/serialization/split_free.hpp:74:5:   instantiated from ‘void boost::serialization::split_free(Archive&, T&, unsigned int) [with Archive = boost::archive::xml_iarchive, T = std::vector<cl_long2>]’
/usr/include/boost/serialization/vector.hpp:151:5:   instantiated from ‘void boost::serialization::serialize(Archive&, std::vector<U, Allocator>&, unsigned int) [with Archive = boost::archive::xml_iarchive, U = cl_long2, Allocator = std::allocator<cl_long2>]’
/usr/include/boost/serialization/serialization.hpp:128:9:   instantiated from ‘void boost::serialization::serialize_adl(Archive&, T&, unsigned int) [with Archive = boost::archive::xml_iarchive, T = std::vector<cl_long2>]’
/usr/include/boost/archive/detail/iserializer.hpp:188:5:   instantiated from ‘void boost::archive::detail::iserializer<Archive, T>::load_object_data(boost::archive::detail::basic_iarchive&, void*, unsigned int) const [with Archive = boost::archive::xml_iarchive, T = std::vector<cl_long2>]’
myFile.cpp:368:2:   instantiated from here
/usr/include/boost/archive/detail/check.hpp:60:5: error: static assertion failed: "typex::value"

The same error appears regardless of whether the archive type is xml or binary. I am using boost::serialization 1.46.

Any hints?

**EDIT: A smaller example including error is at http://ideone.com/4UgCn

Answer 1

If you look at the line where the assertion fails (detail/check.hpp:60), there is a comment right above it:

// trap attempts to serialize objects marked
// not_serializable
BOOST_STATIC_ASSERT(typex::value);

The documentation of this ‘not_serializable’ trait says that you have to enable this long2 type first. As you found out, this is done by:

BOOST_CLASS_IMPLEMENTATION(long2,boost::serialization::object_serializable)