yarp::os::PortablePair crash when using multiple readers

[randaz81]

The following snippet crashes (in a random time <10 seconds) if two yarp read ... /zzz are executed simultaneously.

int main(int argc, char *argv[])
{
    Network yarp;
    typedef yarp::os::PortablePair <yarp::os::Bottle, yarp::os::Bottle> CommandMessage2;
    yarp::os::BufferedPort<CommandMessage2> p;
    p.open("/zzz");
    while (1)
    {
        CommandMessage2& b = p.prepare();
        b.head.clear();
        b.body.clear();
        b.head.addDouble(1.0);
        b.body.addDouble(1.0);
        p.write();
    }
   return 0;
}

The following code, instead, is not affected by this issues. This suggests the fact that the problem may reside in the yarp::os::PortablePair.

int main(int argc, char *argv[])
{
    Network yarp;
    yarp::os::BufferedPort<yarp::os::Bottle> p;
    p.open("/zzz");
    while (1)
    {
        Bottle& b =p.prepare();
        b.clear();
        Bottle& b1 = b.addList();
        Bottle& b2 = b.addList();
        b1.addVocab(VOCAB_VELOCITY_MOVE);
        b1.addInt(2.0);
        b2.addDouble(4.0);
        p.write();
    }
   return 0;
}

Please note that snippet 1 is inspired to RemoteControlBoard.cpp(*) which exhibits the same crash if, for example, two yarp readers are connected to /<client_name>/command:o. This should be thus considered a major bug.

PS:(*) in RemoteControlBoard the following definition is used: typedef yarp::os::PortablePair <yarp::os::Bottle, yarp::sig::Vector> CommandMessage;. In snippet 1, I replaced yarp::sig::Vector with yarp::os::Bottle for simplicity.