Location:
e32std.h
class TCallBack;
Encapsulates a general call-back function.
The class encapsulates:
1. a pointer to a function which takes an argument of type TAny* and returns a TInt.
2. a pointer which is passed to the function every time it is called. The pointer can point to any object. It can also be NULL.
The callback function can be a static function of a class, e.g. TInt X::Foo(TAny *) or it can be a function which is not a member of any class, e.g. TInt Foo(TAny *).
When used with the CIdle
and the CPeriodic
classes, the callback function is intended to be called repeatedly; the encapsulated pointer is passed on each call. Typically,
the pointer refers to an object which records the state of the task across each call. When used with CIdle
, the callback function should also return a true (non-zero) value if it is intended to be called again, otherwise it should
return a false (zero) value.
Defined in TCallBack
:
CallBack()
, TCallBack()
, TCallBack()
, TCallBack()
, iFunction
, iPtr
inline TCallBack(TInt(*aFunction)(TAny *aPtr));
Constructs the callback object with the specified callback function.
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inline TCallBack(TInt(*aFunction)(TAny *aPtr), TAny *aPtr);
Constructs the callback object with the specified callback function and a pointer to any object.
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inline TInt CallBack() const;
Calls the callback function.
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TAny * iPtr;
A pointer that is passed to the callback function when the function is called.