diff -r 51a74ef9ed63 -r ae94777fff8f Symbian3/SDK/Source/GUID-82B73D69-0176-5CBB-B3ED-5CA7F5CCD5D9.dita --- a/Symbian3/SDK/Source/GUID-82B73D69-0176-5CBB-B3ED-5CA7F5CCD5D9.dita Wed Mar 31 11:11:55 2010 +0100 +++ b/Symbian3/SDK/Source/GUID-82B73D69-0176-5CBB-B3ED-5CA7F5CCD5D9.dita Fri Jun 11 12:39:03 2010 +0100 @@ -1,45 +1,45 @@ - - - - - -The -relationship between descriptor classesDescribes inheritance relationship between the descriptor classes -and associated abstract base classes. -

The following diagram shows the inheritance relationship between the concrete -descriptor classes and their abstract base classes.

-

The diagram uses the 16-bit variant types:

- -

but the relationship is exactly the same for the 8-bit variants. The class -names can also be replaced by the build independent types and the relationships -remains valid.

-

The TBufBase16 and TBufCBase16 classes -are an implementation convenience and are not part of the public API.

-

TDesC16 and TDes16 are abstract -classes and cannot be instantiated, However, these types can be passed as -arguments to functions.

- - -

Inheritance relationship between the concrete descriptor classes and their -abstract base classes

- -

Because descriptors are widely used (especially on the stack), the size -of descriptor objects must be kept to a minimum. To help with this, no virtual -functions are defined in order to avoid the overhead of a virtual function -table pointer in each descriptor object.

-

As a consequence, the base classes have implicit knowledge of the classes -derived from them.

+ + + + + +The +relationship between descriptor classesDescribes inheritance relationship between the descriptor classes +and associated abstract base classes. +

The following diagram shows the inheritance relationship between the concrete +descriptor classes and their abstract base classes.

+

The diagram uses the 16-bit variant types:

+
    +

  • TPtrC16

    • +

  • TPtr16

    • +

  • TBufC16 <TInt>

    • +

  • TBuf16 <TInt>

    • +

  • RBuf

    • +

  • HBufC16

    • +
+

but the relationship is exactly the same for the 8-bit variants. The class +names can also be replaced by the build independent types and the relationships +remains valid.

+

The TBufBase16 and TBufCBase16 classes +are an implementation convenience and are not part of the public API.

+

TDesC16 and TDes16 are abstract +classes and cannot be instantiated, However, these types can be passed as +arguments to functions.

+ + +

Inheritance relationship between the concrete descriptor classes and their +abstract base classes

+ +

Because descriptors are widely used (especially on the stack), the size +of descriptor objects must be kept to a minimum. To help with this, no virtual +functions are defined in order to avoid the overhead of a virtual function +table pointer in each descriptor object.

+

As a consequence, the base classes have implicit knowledge of the classes +derived from them.

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