PNotifierFunction Class Reference

#include <notifier.h>

Inheritance diagram for PNotifierFunction:

List of all members.

Public Member Functions
	PNotifierFunction (void *obj)
	Create a notification function instance.
virtual void	Call (PObject &notifier, INT extra) const=0
Protected Attributes
void *	object

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Detailed Description

This is an abstract class for which a descendent is declared for every function that may be called. The PDECLARE_NOTIFIER macro makes this declaration.

The PNotifier and PNotifierFunction classes build a completely type safe mechanism for calling arbitrary member functions on classes. The "pointer to a member function" capability built into C++ makes the assumption that the function name exists in an ancestor class. If you wish to call a member function name that does not exist in any ancestor class, very type unsafe casting of the member functions must be made. Some compilers will even refuse to do it at all!

To overcome this problem, as this mechanism is highly desirable for callback functions in the GUI part of the PTLib library, these classes and a macro are used to create all the classes and declarations to use polymorphism as the link between the caller, which has no knowledege of the function, and the receiver object and member function.

This is most often used as the notification of actions being take by interactors in the PTLib library.

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Constructor & Destructor Documentation

PNotifierFunction::PNotifierFunction

(

void *

obj

)

[inline]

Create a notification function instance.

Parameters:

obj	Object instance on which the function will be called on.

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Member Function Documentation

virtual void PNotifierFunction::Call	(	PObject &	notifier,
		INT	extra
	)			const [pure virtual]

Execute the call to the actual notification function on the object instance contained in this object.

Parameters:

notifier	Object that is making the notification.
extra	Extra information that may be passed to function.

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Member Data Documentation

void* PNotifierFunction::object [protected]

Object instance to receive the notification function call.

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The documentation for this class was generated from the following file:

• notifier.h

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