Conventions Used in This Book

The following typographic conventions are used in this book:

Italic

Used for email addresses and URLs, as well as for new terms where they are defined.

Constant width

Used for code listings and for keywords, variables , function names, command options, module names, directories, filenames, parameters, utilities, program names , and XML elements where they appear in the text.

  Constant width bold  

Used to highlight key fragments of a larger code example, or to show the output of a piece of code.

Constant width italic

Used as a general placeholder to indicate terms that should be replaced by actual values in your own programs.

This icon designates a note, which is an important aside to the nearby text.

This icon designates a warning relating to the nearby text.