run event_based_communication on C++

[owny990312]

when I first run ./example_cxx_event_based_communication_subscriber,
then run ./example_cxx_event_based_communication_publisher, the publisher is coredump like the following picture:

But when I first run example_cxx_event_based_communication_publisher
then run ./example_cxx_event_based_communication_subscriber,it works.

But In my case, it must run subscriber first.

[elfenpiff]

@owny990312 Thanks for the bug-report - I can confirm the bug! It is only present in the C++ version of the example. I suppose it is a bug in the example itself.

[elfenpiff]

@owny990312 the problem was that the publisher and the subscriber had inconsistent history requirements. This is fixed with #567

[owny990312]

@owny990312 the problem was that the publisher and the subscriber had inconsistent history requirements. This is fixed with #567问题是出版商和订阅者的历史要求不一致。这通过 #567 解决了。

Thanks for your reply

[owny990312]

@owny990312 the problem was that the publisher and the subscriber had inconsistent history requirements. This is fixed with #567问题是出版商和订阅者的历史要求不一致。这通过 #567 解决了。

By the way, what is the function of HISTORY_SIZE? Does it store the history messages of the publisher? In other words, can a subscriber receive up to 20 history messages from the publisher?

If I don't set this value, it can work? Because In some case I never mind the history value, so I don't want to subscriber this value.But In my practice, it default to 1 not zero

[elfenpiff]

HISTORY_SIZE determines how many previously delivered samples the publisher will send to the subscriber when the subscriber connects. In this case, the subscriber would receive up to the latest 20 samples from the publisher on connection.