Invalid parameter passed to C runtime function

[wysota]

Perhaps and overcomplicated, but task must be solved. I chose C++11 methods by reason of transparency, have any ideas to solve it?

If it is your school task then we cannot interfere with it, we can only give you hints regarding the use of Qt. I can only suggest to divide your code into classes -- one for the producer, one for the consumer and one for management and user-interface. Then it should be much easier for you to comprehend what is where. If using std::thread is not an explicit requirement then you might want to switch to using QThread.