Cannot send std::map with more than 1 key/value pair

[Tim Jacobs <TimJacobs2@…>]

Sending a std::map (or std::set) of size greater than 1 causes an MPI_ERR_TRUNCATE error. The following code reproduces this error:

#include <boost/mpi.hpp>
#include <boost/serialization/map.hpp>

int
main( int argc, char * argv [] )
{
  boost::mpi::environment env(argc, argv);
  boost::mpi::communicator world;

  if(world.rank()==0){
      std::map<int,int> test;
      test[1]=50;
      test[2]=100;
      world.send(1, 1, boost::mpi::skeleton(test));
      world.send(1, 1, boost::mpi::get_content(test));
      std::cout << "sent" << std::endl;
  }
  else{
      std::map<int,int> test;
      world.recv(0,1,boost::mpi::skeleton(test));
      world.recv(0,1,boost::mpi::get_content(test));
      std::cout << test.size() << std::endl;
  }
}

[Matthias Troyer]

You cannot send sets and maps by skeleton & content, since you need the key values to build the data structure. We should make this give a compile time error.