diff -r 89d6a7a84779 -r 25a17d01db0c Symbian3/PDK/Source/GUID-7809407D-EDC0-5907-B932-0D5726A7ECA2.dita --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/Symbian3/PDK/Source/GUID-7809407D-EDC0-5907-B932-0D5726A7ECA2.dita Fri Jan 22 18:26:19 2010 +0000 @@ -0,0 +1,27 @@ + + + + + +Simple +encapsulation of a service providerThis document describes how to use derived active object classes +to encapsulate services. +

Some active object classes do not implement a RunL() function. +Such classes are intended for derivation.

+

For example, the general purpose CTimer class provides +encapsulation of the timer services offered by the RTimer class, +but provides no RunL() to handle their completion. To use +the CTimer class, you must derive from it again and provide +a RunL() function.

+

Some asynchronous service providers may provide facilities for more than +one request to be outstanding simultaneously. However, a single active object +can only have one request outstanding. If all the facilities of such an asynchronous +service provider must be used in a program, then it must be encapsulated by +more than one active object.

+
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