Technology Documents

Iterators with Complex State

2010-02-04T04:56:00.009-08:00

Programming in LuaPart I. The Language Chapter 7. Iterators and the Generic for7.4 - Iterators with Complex StateFrequently, an iterator needs to keep more state than fits intoa single invariant state and a control variable.The simplest solution is to use closures.An alternative solution is to pack all it needs into a tableand use this table as the invariant state for the

8.4 Additional Documentation Sources

2010-02-04T04:56:00.007-08:00

[ Team LiB ] 8.4 Additional Documentation SourcesWhen looking for source code documentation, consider nontraditional sources such as comments, standards, publications, test cases, mailing lists, newsgroups, revision logs, issue-tracking databases, marketing material, and the source code itself. When investigating a large body of code, it is natural to miss documentation embedded in comments in

Non-Preemptive Multithreading

2010-02-04T04:56:00.005-08:00

Programming in LuaPart I. The Language Chapter 9. Coroutines9.4 - Non-Preemptive MultithreadingAs we saw earlier, coroutines are a kind ofcollaborative multithreading.Each coroutine is equivalent to a thread.A pair yield-resume switches control from one thread to another.However, unlike "real" multithreading,coroutines are non preemptive.While a coroutine is running, it cannot be

Recipe 8.6. Building a Query String

2010-02-04T04:56:00.003-08:00

Recipe 8.6. Building a Query String8.6.1. ProblemYou need to construct a link that includes name/value pairs in a query string.8.6.2. SolutionUse the http_build_query( ) function, as in Example 8-14.Building a query string 'Oscar the Grouch', 'color' => 'green', 'favorite_punctuation' => '#');$query_string = http_build_query($vars);$url = '

Introduction

2010-02-04T04:56:00.001-08:00

IntroductionPain is a wonderful learning tool. It's nature's way of saying, "Don't do that!" If you are a programmer, you've had your share of pain. It usually occurs about 2:00 in the morning as you finally find that one last bug that has been tormenting you for the past two weeks.The book is filled with buggy programs. This allows you to learn from the misfortunes of others. It contains bugs

Section 7.1. Defining a Simple Class

2010-02-04T04:55:00.023-08:00

Chapter 7. Classes and Modules Ruby is an object-oriented language in a very pure sense: every value in Ruby is (or at least behaves like) an object. Every object is an instance of a class. A class defines a set of methods that an object responds to. Classes may extend or subclass other classes, and inherit or override the methods of their

7.7 Nagios

2010-02-04T04:55:00.021-08:00

[ Team LiB ] 7.7 NagiosWhile Sysmon is a good package that takes care of the needs of the average network administrator, it does have a few limitations that can be serious drawbacks for very large networks. Nagios,[2] available from http://www.nagios.org/, is better suited to these installations. Some of the major advantages of Nagios are:[2] According to the Nagios Web site, the name is

Arithmetic Metamethods

2010-02-04T04:55:00.019-08:00

Programming in LuaPart II. Tables and Objects Chapter 13. Metatables and Metamethods13.1 - Arithmetic MetamethodsIn this section, we will introduce a simple exampleto explain how to use metatables.Suppose we are using tables to represent sets,with functions to compute the union of two sets,intersection, and the like.As we did with lists,we store these functions inside a tableand we

Chapter 22. Flocking Boids

2010-02-04T04:55:00.017-08:00

Chapter 22. Flocking BoidsFlocking is a computer model for the coordinated motion of groups (or flocks) of entities called boids. Flocking represents group movementas seen in bird flocks and fish schoolsas combinations of steering behaviors for individual boids, based on the position and velocities of nearby flockmates. Though individual flocking behaviors (sometimes called rules) are quite

Recipe 1.17. Program: Downloadable CSV File

2010-02-04T04:55:00.015-08:00

Recipe 1.17. Program: Downloadable CSV FileCombining the header( ) function to change the content type of what your PHP program outputs with the fputcsv( ) function for data formatting lets you send CSV files to browsers that will be automatically handed off to a spreadsheet program (or whatever application is configured on a particular client system to handle CSV files). Example 1-39

Section 1.6. How Does Open Source Grow?

2010-02-04T04:55:00.013-08:00

1.6. How Does Open Source Grow?So, there the inspired developer sits, with a handful of competent developers contributing to the project, all of them working away to make the software better. How does this work? The inspired developer is now the acknowledged leader of the project, but the position doesn't come with much authority. Frequently, no legal agreements of any kind define the

Other Fractal Landscapes

2010-02-04T04:55:00.011-08:00

Other Fractal LandscapesAside from the plasma fractal used in my code, two other popular approaches are the fault fractal and the Fractal Brownian Motion (FBM) fractal.A fault fractal creates a height map by drawing a random line through a grid and increasing the height values on one side of the line. If this is repeated several hundred times then a reasonable landscape appears. The main

Debuggers

2010-02-04T04:55:00.009-08:00

[ LiB ]DebuggersRuby comes with a debugger, accessible on the command line, for stepping through problems with programs (see Figure 9.1). Type the following to access it:Figure 9.1. Accessing the Ruby command-line debuggerRuby r debug MyProgramScript.rbThe debugger has a number of useful commands for, well, debugging a Ruby program. These are listed in Table 9.1.Table 9.1. Debug CommandsCommand

A Generic Call Function

2010-02-04T04:55:00.007-08:00

Programming in LuaPart IV. The C API Chapter 25. Extending your Application25.3 - A Generic Call FunctionAs a more advanced example,we will build a wrapper for calling Lua functions,using the vararg facility in C.Our wrapper function (let us call it call_va) receives thename of the function to be called,a string describing the types of the arguments and results,then the list of

Verifying Implementation

2010-02-04T04:55:00.005-08:00

[ Team LiB ] Verifying ImplementationGP 2.9 Objectively Evaluate AdherenceObjectively evaluate adherence of the integrated project management process against its process description, standards, and procedures, and address non-compliance. ElaborationExamples of activities reviewed include the following:Establishing, maintaining, and using the project's defined processCoordinating and

Puzzle 14: Escape Rout

2010-02-04T04:55:00.003-08:00

< Day Day Up > Puzzle 14: Escape RoutThe following program uses two Unicode escapes, which represent Unicode characters by their hexadecimal numeric codes. What does the program print?public class EscapeRout { public static void main(String[] args) { // \u0022 is the Unicode escape for double quote (") System.out.println("a\u0022.length() + \u0022b".length()); }}Solution 14: Escape RoutA

Section 6.2. Getting Dates In and Out of a Database

2010-02-04T04:55:00.001-08:00

6.2 Getting Dates In and Out of a DatabaseIn the real world, dates are not alwaysrepresented using Oracle's DATE datatype. At varioustimes, we'll need to convert DATEs to otherdatatypes and vice versa. This is particularly true when we interfacean Oracle database with an external system, for example when we areaccepting date input from an external system in which dates

DO'S AND DON'TS

2010-02-04T04:54:00.053-08:00

DO’S AND DON’TSNow that you’ve read about the most important aspects of planning and managing a CMMI process improvement project, here are some but not all of the lessons in abbreviated form.DoReuse as much as possible.Make sure everyone is speaking the same language as a prerequisite to starting the CMMI process improvement project.Use appraisals or other methods to characterize the organization

Image-Processing Utilities

2010-02-04T04:54:00.051-08:00

Image-Processing UtilitiesTheGIMPBeyond a doubt, the best image-processingprogram available for Linux is called the GIMP, or GNU Image ManipulationProgram. It is released under the GNU General Public License, so source code isavailable, and it is built to allow easy integration of third-party extensions.It is often compared to Adobe's Photoshop in the breadth of its features. LikePhotoshop, the

Section 4.27. The Target Attribute Exposed

2010-02-04T04:54:00.049-08:00

4.27. The Target Attribute ExposedThis week's interview:Using target considered bad? Head First: Hello target, we're so glad you could join us.Target Attribute: I'm glad to be here. It's nice to know you're still interested in hearing about me.Head First: Why do you say that?Target: Well, to be honest, I'm not as popular as I used to be.Head First: Why do you think that is?Target: I think it's

Day 17. Moving Data

2010-02-04T04:54:00.047-08:00

[ Team LiB ] Day 17. Moving DataToday, you see how to move data in and out of a DB2 database by importing, loading, or exporting:If you want to create a new database, replace data in an existing database, or append to the data in an existing database with data from another source, you use the Import utility.If you have a substantial amount of data that you need to move into your database,

Granting Privileges to Other Users

2010-02-04T04:54:00.045-08:00

[ Team LiB ] Granting Privileges to Other UsersTo give privileges to the SAMPLE database to other users on the system, follow these steps:Start the Control Center, if it isn't already started.Expand the objects until you see the SAMPLE database.Right-click the SAMPLE database folder and select Authorities from the pop-up menu.In the Database Authorities � SAMPLE window, click Add User, select

Comments and Questions

2010-02-04T04:54:00.043-08:00

Comments and QuestionsWe have tested and verified the information in this book to the best of our ability, but you may find that features have changed (or even that we have made mistakes!). Please let us know about any errors you find, as well as your suggestions for future editions, by writing to:O'Reilly Media, Inc.1005 Gravenstein Highway NorthSebastopol, CA 95472(800) 998-9938 (in the U.S. or

7.4 Examining a Sample Policy

2010-02-04T04:54:00.041-08:00

< Day Day Up > 7.4 Examining a Sample PolicySeeing the syntax of individual policydeclarations is not the same as seeing how they work together toestablish a useful policy. In this section, we'lllook at the policy that governs the ping_t domain,and the related domain ping_exec_t, as implementedin Fedora Core 2. Like most policies, this policy resides in twofiles:file_contexts/program/

SDL

2010-02-04T04:54:00.039-08:00

SDLRequires:lang=EN-GB> a soundcardNext, I had to upgrade my copy of SDL! SDL isthe simple direct media layer, which is required for avifile.Basically, it's designed to give quick access to your video and audiodevices�so the sound is nice and the video plays back at a watchable speed. Likemost of the packages, downloading, compiling, and installing it was simple. Igrabbed libsdl-1.1.7, which was

Section E.3. Recommended Open Source Content Management System Projects

2010-02-04T04:54:00.037-08:00

E.3. Recommended Open Source Content Management System ProjectsThe projects we focus on in this section include:PlonePlone is a content management system that can be used as a portal, a document management system, an intranet server, an extranet server, or a collaboration server.DrupalDrupal is a content management system for building dynamic web sites for a broad range of projects, from personal

Section 4.9. Embedded Database

2010-02-04T04:54:00.035-08:00

4.9. Embedded DatabaseAdobe AIR includes an embedded SQLite database that AIR applications can leverage. SQLite is a compact open source database that supports ACID transactions, requires zero configuration, implements most of SQL92, and supports strings and BLOBs up to 2 GB in size. All database information is stored in a single file on disk, which you can freely share between

Secure Shell (SSH)

2010-02-04T04:54:00.033-08:00

Secure Shell(SSH)We've already looked at public-keycryptography and we've shown you how you can use GPG to secure your e-mail. Nowwe are going to show you another program that uses similar cryptographictechniques to encrypt data streams between client and server programs ondifferent machines. This section will show the basics: Using SSH to have"encrypted Telnet" sessions and using SCP (secure

Chapter 18. Remote CD Burning

2010-02-04T04:54:00.031-08:00

Chapter 18. Remote CDBurning style='width:90.0%'> lang=EN-GB style='font-size:16.5pt;font-family:Arial'>Difficult-o-Meter: 2 (light Linux skill required) Covers: style='width:90.0%'> color:black'>cdrecord color:black'>http://www.fokus.gmd.de/research/cc/glone/employees/joerg.schilling/private/cdrecord.html color:black'>mkisofs

Introduction

2010-02-04T04:54:00.029-08:00

IntroductionMy first exposure to 3D graphics was quite awhile ago, when Linux was still relatively new. I was at a new job and wantedto learn something about 3D graphics. I decided to make a 3D version of thecompany logo. A friend suggested I use a program called PovRay. The companylogo turned out great and I learned a lot from the project. I learned somethingabout 3D art and also about messing

Software Needed to Complete the Examples

2010-02-04T04:54:00.027-08:00

Ru-Brd Software Needed to Complete the ExamplesAll of the examples in this book, along with extras not in the book, can be downloaded from Addison-Wesley's Web site for this book: http://www.awprofessional.com/titles/0672324083. At a minimum, you will need to have a J2SE JDK and a JMX implementation installed on your computer to compile and run the samples shown throughout this book. These

Program 48: File Follies

2010-02-04T04:54:00.025-08:00

Program 48: File FolliesThe following program works just fine for a while, and then it refuses to recognize files that contain the magic number: 1 /************************************************ 2 * scan -- Scan a directory tree for files that * 3 * begin with a magic number. * 4 ************************************************/ 5 #include 6 #include <

Introduction

2010-02-04T04:54:00.023-08:00

< Day Day Up > IntroductionOne of the last frontiers in creating atruly CSS-enabled presentation is the layout. For a long time, webdevelopers have been using HTML tables to create their layouts,often nesting tables to create multicolumn, multilevel layouts.Nested HTML tables render well in older browsers like NetscapeNavigator 4 where CSS support, if present, is barely noticeable andis mostly

Appendix A: Case Studies and Schema Objects

2010-02-04T04:54:00.021-08:00

Appendix A: Case Studies and Schema ObjectsOverviewThe following case studies and schema objects are used in various chapters of this book. SQL and PL/SQL code can be executed in a number of ways, such as from a Java/JDBC application, as embedded SQL/PL/SQL calls from Java, from an IDE such as SQL*Plus, or invoked as SQL/PL/SQL calls from a front application such as Oracle Forms or Visual Basic.

Conventions Used in This Book

2010-02-04T04:54:00.019-08:00

Conventions Used in This BookThe following typographical conventions are used in this book:Plain textIndicates menu titles, menu options, menu buttons, and keyboard accelerators (such as Alt and Ctrl).ItalicIndicates new terms, URLs, email addresses, filenames, file extensions, pathnames, directories, and Unix utilities.BoldEmphasizes important text.Constant widthIndicates commands, options,

Program 82: The Case of the Disappearing Array

2010-02-04T04:54:00.017-08:00

Program 82: The Case of the Disappearing ArrayWe have a simple array class and an even simpler test routine. Yet somehow memory gets corrupted. 1 /************************************************* 2 * var_array -- Test variable length array * 3 * class. * 4 *************************************************/ 5 #include 6 7 /********