yarp::os::Subscriber segfault when using callback

[randaz81]

The following code leads to a segfault (the first time data are received)

m_dataReader->new DataReaderClass;
m_dataReader->useCallback();
m_dataReader->topic("/ros_topic");

while the following is ok:

m_dataReader->new DataReaderClass;
m_dataReader->topic("/ros_topic");
m_dataReader->useCallback();

Being DataReaderClass defined as:

class DataReaderClass: public yarp::os::Subscriber<ros_msg_type>

The issue could be related to the fact that topic() automatically creates a connection? (The connection is typically created later when using a standard buffered port with callback, instead).

[randaz81]

I can confirm this bug is still present in yarp 3.3 [master branch]

Additional note: if I use a yarp::os::Port class, I am able to call the useCallback() method before or after the .open() method with no segfault. So this bug seems to be somehow specific for the yarp::os::Subscriber class.

[ste93]

Same error happened today, This is the backtrace generated by gdb. It seems that the topic is not completely started when the first callback is called