Boost Interprocess Send giving error: boost::interprocess_exception::library_error - boost

Question

I am using boost message queue to communicate among different processes. I am transmitting an object of type Packet. To do this, I am using serialization and deserialization in send and receive functions.
However, when I try to send the data, I am getting this error:
boost::interprocess_exception::library_error
No other information is given.
This is how I create message queues.
for(i = 0; i< PROC_MAX_E ; i++){
std::string mqName = std::string("mq") + std::to_string(i);
std::cout << " Size of Packet is " << sizeof(Packet) << std::endl;
message_queue mq(open_or_create, mqName.c_str(), MAX_QUEUE_SIZE_E, 100*sizeof(Packet)); // size of packet later
}
This is my Packet :
class Packet{
public :
Packet();
Packet(uint32_t aType, uint32_t aProcId);
~Packet();
uint32_t getType();
union{
uint32_t mFuncId;
//uint8_t mResult8;
uint32_t mResult32;
//uint64_t mResult64;
//bool mResult;
//uint8_t* mAddr8;
//uint32_t* mAddr32;
//uint64_t* mAddr64;
//char mData[MAX_PACKET_SIZE]; // This will be used to store serialized data
};
friend class boost::serialization::access;
template <class Archive>
void serialize(Archive & ar, const unsigned int version){
ar & _mType;
ar & _mProcId;
//ar & mData;
ar & mFuncId;
//ar & mResult32;
}
private :
uint32_t _mType;
uint32_t _mProcId;
}; // end class
} // end namespace
This is my serialize and deserialize functions:
std::string IPC::_serialize(Packet aPacket){
std::stringstream oss;
boost::archive::text_oarchive oa(oss);
oa << aPacket;
std::string serialized_string (oss.str());
return serialized_string;
}
Packet IPC::_deserialize(std::string aData){
Packet p;
std::stringstream iss;
iss << aData;
boost::archive::text_iarchive ia(iss);
ia >> p;
return p;
}
And this is my send and receive functions:
bool IPC::send(uint32_t aProcId, Packet aPacket){
try{
_mLogFile << "<-- Sending Data to Process : " << aProcId << std::endl;
//uint32_t data = aPacket;
std::string mqName = std::string("mq") + std::to_string(aProcId);
message_queue mq(open_only, mqName.c_str());
//serialize Packet
std::cout << "Serializing \n";
std::string data = _serialize(aPacket);
std::cout << " Serialized data =" << data.data() << "Size = " << data.size()<< std::endl;
mq.send(data.data(), data.size(), 0);
//mq.send(&data, sizeof(uint32_t), 0);
}catch(interprocess_exception &ex){
_mLogFile << "***ERROR*** in IPC Send to process : " << aProcId << " " << ex.what() << std::endl;
std::cout << "***ERROR*** in IPC Send to process : " << aProcId << " " << ex.what() << std::endl;
_ipc_exit();
}
}
I am getting exception during mq.send
When I transmit only integers it works fine. Only with serialization and deserialization, I get this error
Any help is greatly appreciated.I am a little stuck as the exception message is also not clear.
I am using boost 1_57_0
Rgds
Sapan

Answer 1

Try closing or flushing the string steam before using the string.
std::string IPC::_serialize(Packet aPacket){
std::stringstream oss;
{
boost::archive::text_oarchive oa(oss);
oa << aPacket;
}
return oss.str();
}