Calling arbitrary callbacks from a destructor is a bad idea. Sooner or later someone will violate the requirement about exceptions, and your program will be ter

Calling arbitrary callbacks from a destructor is a bad idea. Sooner or later someone will violate the requirement about exceptions, and your program will be terminated immediately. So I'd only use this pattern in -fno-exceptions projects. In a similar vein, care must be taken when calling arbitrary callbacks while iterating a data structure - because the callback may well change the data structure being iterated (classic example is a one-shot event handler that unsubscribes when called), which will break naïvely written code.