2

I´m reading a message queue, using Boost.Serialization (v1.46). Everything works fine as long as the queue contains only one element. But when I read a queue which contains more than one element the, following exception is thrown:

terminate called after throwing an instance of 'boost::archive::archive_exception' what(): invalid signature

The archive_exception.hpp says invalid signature // first line of archive does not contain expected string"

The class I´m serializing and deserializing looks as followed:

#define MAX_SIZE 1000 class IpcMsg { public: IpcMsg(int logLevel = 0, std::string logMsg = "") : logLevel(logLevel), logMsg(logMsg) { } ; int logLevel; std::string logMsg; private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & logLevel; ar & logMsg; } };

serializing :

try { message_queue mq ( open_or_create, "mq", 100, MAX_SIZE ); IpcMsg logMsg(1, "Test"); std::stringstream oss; boost::archive::text_oarchive oa(oss); oa << logMsg; std::string serialized_string(oss.str()); mq.send(serialized_string.data(), serialized_string.size(), 0); } catch(interprocess_exception &ex) { std::cerr << ex.what() << std::endl; }

deserializing:

... IpcMsg logEntry; std::stringstream iss; std::string serialized_string; serialized_string.resize(MAX_SIZE); while(mq.try_receive(&serialized_string[0], MAX_SIZE, recvd_size, priority)){ iss << serialized_string; boost::archive::text_iarchive ia(iss); ia >> logEntry; msgs.push_back(logEntry); std::cout << logEntry.logLevel << std::endl; std::cout << logEntry.logMsg << std::endl; }

Improve this question
0

1 Answer 1

Reset to default
1

This code creates a std::stringstream consisting of the message followed by up to MAX_SIZE null characters.

serialized_string.resize(MAX_SIZE); mq.try_receive(&serialized_string[0], MAX_SIZE, recvd_size, priority); iss << serialized_string;

I'm guessing Boost.Serialization is hitting the NULL characters that are after the first message and erroring out.

Maybe you could try something like this instead?

serialized_string.resize(MAX_SIZE); mq.try_receive(&serialized_string[0], MAX_SIZE, recvd_size, priority); serialized_string.resize(recvd_size); iss << serialized_string;

(Also, I'm not personally a fan of code like &serialized_string[0]. See here, here. A vector<char> or smart pointer to a plain old char[] might be better.)

Improve this answer
Sign up to request clarification or add additional context in comments.

Comments