Inside Distributed COM Comments and Corrections (189199)

SUMMARY

This article contains comments, corrections, and information about known errors relating to the Microsoft Press book Inside Distributed COM, ISBN 1-57231-849-X.

The following topics are covered:

Page 52: Reflexive and Symmetric Used Incorrectly

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Page 52: Reflexive and Symmetric Used Incorrectly

The terms "Reflexive" and "Symmetric" are used incorrectly to describe QueryInterface rules. The correct meaning of these terms is as follows:

Reflexive: (A=A)
Symmetric: (if A=B, then B=A)

To correct the book, the terms should be swapped. Specifically, page 52 should be changed in the following ways:

QueryInterface must be reflexive. If a client holds a pointer to an interface and queries for that same interface, the call must succeed. QueryInterface must be symmetric. If a client holding a pointer to one interface queries successfully for a second interface, the client must be able to call QueryInterface through the second pointer for the first interface.

Swap Reflexive and Symmetric labels on Figure 2-4. Microsoft Press is committed to providing informative and accurate books. All comments and corrections listed above are ready for inclusion in future printings of this book. If you have a later printing of this book, it may already contain most or all of the above corrections.