Inheritance diagram for csp::PoisonException:
This exception is thrown when you try to use a channel that is poisoned. Unlike derivatives of CPPCSPError, this exception does not mean your program is in error; in fact, it is usual for it to be thrown at the end of a program's lifetime.
The use of poison, and therefore of PoisonException, is explained on the Poison page and also in the Channel Poison section of the guard.