I am trying to get some (hitherto) windows code to compile on a unix machine but am getting some errors at the following method:
namespace EDIN {
void World::Save(char const filename[])
{
std::ofstream ofs(filename);
boost::archive::text_oarchive oa(ofs);
oa << this << cellSequence << report; // line 590: error!
}
}
The error looks like this:
test.cpp: In member function ‘void EDIN::World::Save(const char*)’: test.cpp:122:12: error: no match for ‘operator<<’ (operand types are ‘boost::archive::text_oarchive’ and ‘EDIN::World*’) oa << this << cellSequence << report; // line 590: error! ^ test.cpp:122:12: note: candidate is: In file included from /home/armanschwarz/lib/boost_1_55_0/boost/archive/detail/common_oarchive.hpp:22:0, from /home/armanschwarz/lib/boost_1_55_0/boost/archive/basic_text_oarchive.hpp:32, from /home/armanschwarz/lib/boost_1_55_0/boost/archive/text_oarchive.hpp:31, from test.cpp:1: /home/armanschwarz/lib/boost_1_55_0/boost/archive/detail/interface_oarchive.hpp:62:15: note: Archive& boost::archive::detail::interface_oarchive::operator<<(T&) [with T = EDIN::World*; Archive = boost::archive::text_oarchive] Archive & operator<<(T & t){ ^ /home/armanschwarz/lib/boost_1_55_0/boost/archive/detail/interface_oarchive.hpp:62:15: note: no known conversion for argument 1 from ‘EDIN::World*’ to ‘EDIN::World*&’
I'm using boost 1.55.0 (same as when I used to compile this on Visual Studio). Can anyone spot what I'm doing wrong here?
Here is a self-contained example from sehe:
#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <boost/serialization/serialization.hpp>
#include <boost/serialization/vector.hpp>
#include <boost/serialization/string.hpp>
#include <boost/serialization/valarray.hpp>
#include <chrono>
namespace EDIN
{
struct Region
{
int id;
Region(int id = 42) : id(id) {}
private:
friend class boost::serialization::access;
template<class Archive> void serialize(Archive & ar, const unsigned int file_version)
{
ar & id;
}
};
struct Scheme
{
std::string GetSchemeType() const { return "scheme_type_42"; }
};
class World
{
// dummy members to make it compile
// will be different things of course
int mass, epoch;
std::chrono::system_clock::time_point _start;
std::string report;
public:
std::vector<int> cellSequence; // for demo, public
World(std::string&, EDIN::Region&, unsigned int&, const std::chrono::system_clock::time_point&)
: mass(99), epoch(88), _start(std::chrono::system_clock::now()), report("Report101")
{
// TODO!
}
Region Bounds() const { return Region(); }
int Epoch() const { return epoch; }
EDIN::Scheme Scheme() const { return EDIN::Scheme(); }
std::chrono::system_clock::time_point StartingWallTime() const {
return _start;
}
World()
: mass(99), epoch(88), _start(std::chrono::system_clock::now()), report("Report101")
{
}
void Save(char const filename[]);
static World* Load(char const filename[]);
private:
friend class boost::serialization::access;
template<class Archive> void serialize(Archive & ar, const unsigned int file_version)
{
ar & mass & epoch;
}
};
}
namespace boost
{
namespace serialization
{
template<class Archive>
inline void save_construct_data(Archive & ar, EDIN::World const * t, unsigned const int file_version)
{
time_t const totalRunningTime = std::chrono::duration_cast<std::chrono::duration<time_t, std::milli>>(
std::chrono::system_clock::now() - t->StartingWallTime()).count();
EDIN::Region const bounds = t->Bounds();
time_t const epoch = t->Epoch();
std::string tmp = t->Scheme().GetSchemeType();
ar
<< bounds
<< epoch
<< totalRunningTime
<< tmp;
}
template<class Archive>
inline void load_construct_data(Archive & ar, EDIN::World * t, const unsigned int file_version)
{
EDIN::Region bounds;
unsigned epoch;
time_t totalRunningTime;
std::string schemeType;
ar >>
bounds >>
epoch >>
totalRunningTime >>
schemeType;
std::chrono::system_clock::time_point const startingWallTime =
std::chrono::system_clock::now() - std::chrono::duration<time_t, std::milli>(totalRunningTime);
::new(t) EDIN::World(schemeType,bounds,epoch,startingWallTime);
}
}
}
#include <fstream>
namespace EDIN {
void World::Save(char const filename[])
{
std::ofstream ofs(filename);
boost::archive::text_oarchive oa(ofs);
oa << this << cellSequence << report; // line 590: error!
}
World* World::Load(char const filename[])
{
World *world = 0;
std::ifstream ifs("world.save");
boost::archive::text_iarchive ia(ifs);
ia >> world;
ia >> world->cellSequence >> world->report;
return world;
}
}
int main()
{
EDIN::World world;
world.cellSequence.push_back(12345);
world.cellSequence.push_back(-6767);
world.Save("world.save");
EDIN::World* restored = EDIN::World::Load("world.save");
restored->Save("world2.save");
delete restored;
}
It compiles fine here using GCC 4.8.1 and Boost 1.55.0. I am using GCC 4.9.0 and boost 1.55.0.
EDIT: I have found a hack that seems to work:
The problem seems to be that G++ 4.9 doesn't want to cast World::this from World* to World*&. Replacing the World::Save method with the following resolves the problem:
void World::Save(char const filename[])
{
std::ofstream ofs(filename);
boost::archive::text_oarchive oa(ofs);
World* thisCopy = this;
oa << thisCopy << cellSequence << report;
}
There seems to be a difference in behaviour between GCC 4.8.1 and GCC 4.9 that causes the latter not to compile unless I create copy of the this pointer. If someone could point out why this is happening and whether or not it's a bug or intended change in behaviour that would be appreciated!
