[preface]
== Preface

=== Conventions Used in This Book

The following typographical conventions are used in this book:

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+Constant width+:: Used for program listings, as well as within paragraphs to refer to program elements such as variable or function names, databases, data types, environment variables, statements, and keywords.

**`Constant width bold`**:: Shows commands or other text that should be typed literally by the user.

_++Constant width italic++_:: Shows text that should be replaced with user-supplied values or by values determined by context.


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=== Using Code Examples
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=== Acknowledgments


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