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This could potentially cause unexpected or different behavior between zero-filled heap-based and non-zeroed stack-based objects. For this reason, among others such as managing cleanup in the event of a leave, objects of a C class must always be allocated on the heap. Clearly, when it is no longer needed, a heap-based object must be destroyed. Objects of C classes typically exist either as pointer members of another class or are accessed by local pointer variables. If owned, the CBase-derived object should be destroyed by a call to delete, for example in the destructor of the owning class.

TAny* should be used in preference to void*, effectively replacing it with a typedef’d ”pointer to anything”. TAny is thus equivalent to void but, in the context where void means ”nothing”, it is not necessary to replace the native void type. Thus, a function taking a void* pointer (to anything) and returning void (nothing) will typically have a signature as follows on Symbian OS: void TypicalFunction(TAny* aPointerParameter); This is the one exception to the rule of replacing a native type with a Symbian OS typedef; it occurs because void is effectively compiler-independent when referring to ”nothing”.

H). This class has two characteristics which are inherited by its subtypes and thus guaranteed for every C class. Firstly, CBase has a virtual destructor so a CBase-derived object may be destroyed properly by deletion through a CBase pointer. This 2 In case you are wondering, the ”C” stands for ”Class”, which perhaps makes a ”C class” something of a tautology, though it is an accurate reflection of the fact that it is more than the simple ”Type” described by a T class. C CLASSES 5 is common when using the cleanup stack, since the function invoked when pushing a CBase-derived object onto the cleanup stack is the CCleanupStack::PushL(CBase* aPtr) overload.