Read an Excerpt
The Win32 system services are the innovative, cuttingedge capabilities that make Windows 2000 and Windows 98 interesting and exciting. Amid all of the media attention surrounding Windows 2000 and 98, you have probably heard and read about many of the modern capabilities that these operating systems contain:
- Processes and threads
- Remote Procedure Calls (RPCs) and DCOM (Distributed COM)
- Event logging
- Network communications
- TCP/IP network communications
- File mapping and Active Directory
- Interprocess and Interprocessor communication
- Compressed file access
- Network drive and printersharing
- Serial communications
- Services (background processing like UNIX daemons)
- Object and file security
The goal of this book is to show you how to use all of these different services in your own applications. This book contains hundreds of concise, clear, and easytounderstand example programs and explanations. The examples show you how to access the system services listed above, as well as many others. You can use these examples directly, to understand the concepts. You can also drop the sample code into your own programs and then extend it to give your applications new and useful features.
By learning about the many and varied system services available inside of Windows 2000 and 98, you can make your programs much more interesting to the user. For example, if you learn about threads and then add multiple threads to your applications, the user gets a much smoother interface (see Chapter 6). Your program will also takeadvantage of multiple processors on machines that have them. If you add network support to your applications, the user is able to access network resources that are unavailable on a single machine (see Chapter 8). If you add modem support, you can use it to let the user dial into a remote system (see Chapter 11). Or you might use a modem to let the user dial a support line or registration system for a product that your company sells.
The goal of this book is to give you a thorough and clear understanding of the system services so that you can take advantage of all of the capabilities that Windows has to offer.
This book is designed for two types of people. If you are a devoted connoisseur or student of programming, the study of the system functions is interesting in its own right. It's fun to see what functions are available, and to try to think of ways to exploit those capabilities. One way to use this book is to simply browse through it and see what is possible. You can work with the examples and extend them in ways that you find enjoyable.
If, on the other hand, you are a programmer with a deadline, enjoyable entertainment is probably not your goal. You may have looked at the huge number of functions in the Windows API and found it discouraging. Where do you start? What you need is a set of useful examples and clear explanations that quickly solve your specific problems. You will find this book useful because it organizes concepts logically and provides the material that you need to master a specific topic very quickly.
If you are migrating from another operating system to Windows, this book will help you to quickly map your existing knowledge into the Windows framework. See Chapter 1 for a list of the 121 most common programming questions in Windows, as well as for the locations of the sections that contain the answers.
This book is organized by functional categories. For example, Chapter 2 talks about all of the functions that pertain to file input/output and file handling. Chapter 3 deals with disk drives. Chapter 4 discusses directories. Chapter 5 talks about the nextgeneration directory services, known as Active Directory in Windows 2000. Chapter 6 talks about processes and threads. You will find that each chapter starts with a general overview of the topic, followed by sections that describe and give examples for subsets of functions.
In many chapters you will find integrating examples that combine different capabilities from several chapters to create larger applications. Many of these larger examples form complete applications that you can use as starting points for new projects of your own.
Several principles guide the content of this book. The first principle is the most important and is therefore used throughout: it is simplicity. There is nothing worse than looking up a function, only to find that its example is embedded within sample code that takes three days to comprehend because it is 28 pages long. In all cases a function is first demonstrated in code that is as simple as possible so that you can extract the essence of each one very quickly. They may then be integrated into larger examples. In many cases you will look at the example code and say to yourself, "This is easy!" That is exactly the intent. If the book makes everything look simple and easy for you, then it has accomplished its goal.
The second principle driving this book is the idea of functional families. Functions in the 32bit API very rarely exist on their ownit is far more common to find small collections of functions that relate very closely to one another. For example, the ReadFile function reads from a file, but you must open the file with CreateFile before you can read from it and then remember to close it with CloseHandle afterwards (see Chapter 2). These functions belong to a family. In this book you will generally find small groupings of functions described as logical units.
The third principle in this book is that of currency. The Windows API has been around for some time, and when you look at it you will find that there is a certain amount of layering. The documentation will often say things like, "this function is retained for compatibility with version 1.8, but has been superseded by function xyz." This book deals only with the current functions, and leaves the superseded ones to die in peace.
The last principle guiding this book is independence. Each chapter in this book is as standalone as possible, so that you can jump around in the book as you please. In cases where material from other chapters is important, you will find references to the related sections.
Prerequisites and Languages
This book makes no assumptions about your former knowledge of systems programming in Windows or in any other system. Its only real assumption is that you know C and/or C++. You will find that the example code can be divided into two categories:
- Text examples that run in "console mode." These programs run from the MSDOS prompt, accept keyboard input, and produce text output. They form the vast majority of the code in this book because they are simple. These programs are C++ compatible, but the only elements really being used from C++ are the I/O stream libraries.
- "Windows" programs that use the Windows GUI. These programs use C++ and the Microsoft Foundation Class library (MFC). The book Visual C++: Developing Professional Applications for Windows 98 and NT using MFC, by Marshall Brain and Lance Lovette (ISBN 0130851213), describes how to create programs with MFC, and will be useful as a tool to help you understand these examples if you are not already familiar with MFC. You can develop Clanguage Windows programs using only the Win32 API. However, the Visual C++ tools make lowlevel Win32 programming easier. But to take advantage of the Visual C++ and MFC tools, you should have a good grasp of the underlying Win32 API.
If you are a C programmer with no C++ experience, you will have no trouble understanding the console programs. The only unusual thing you will see is code that looks like this:
char s100;// Prompt the usercout << "Enter a line of text: ";// Read a line of text from the usercin.getline(s,100);// Echo the user's input to stdoutcout << s << endl;
This code declares a character string s, and then uses "cout <<" to output a prompt to the user. The "cin.getline" statement reads a line of text from the user. The final "cout" statement echoes the line. The book Visual C++: Developing Professional Applications in Windows 95 and NT using MFC, by Marshall Brain and Lance Lovette (ISBN 0133051455), contains an extensive C++ appendix to help you get started with the language if you are interested. It will also help you understand the MFC code.
The Diskette and the Online Index
The diskette included with this book contains the source code for all of the examples in the book, as well as the source and data for an online indexing program. The index is broken down by sections and includes every word found in the manuscript.
To use the index, follow the directions in the README file on the disk to compile the program. When you run the index, you will see a display that contains an edit area, three buttons (Help, Search and Quit), and a list area. Any words that you type in the edit area are used to search for appropriate sections. For example, if you want to find out how to create a DLL entry point, you would type "DLL entry point" in the edit area. Press the "Search" button to begin the search. The index program will list all sections that contain all three of those words. Enter as many words as you like to home in on what you want. Word matching is exact and caseinsensitive. If a word does not appear in the book, the program will tell you.
There are many cases where an exact match does not work well. For example, there may be a section that contains "thread" and "create" but not "creating" and "threads," so if you enter the line "creating threads" on the edit line you get no matches. You can use the "*" wild card character at the end of a word to solve this problem. For example, by entering "creat*" the system will use OR to gather together all words with the root "creat" ("create," "creates," "creation," etc.). You may want to get in the habit of using the wild card character at the end of all words: "creat* thread*," for example. This often yields more helpful results.
If an obvious word seems to be missing from the index, try to find it in the book to make sure you are spelling it correctly. For example, "resize" is spelled "resize" in the book, and you need to spell it the same way.
Contents of the Book
Each chapter in this book talks about a different service in the 32bit API. Chapter 1 contains a list of the 121 most common questions about the system services, and it will help you to quickly find material that interests you. The list below summarizes the different chapters in the book to help you with browsing.
- Chapter 1 is an introduction. It contains a list of the 121 most common programming questions about the Windows system services. This list will serve as a good road map for you. The chapter also contains general information that is useful throughout the book.
- Chapter 2 discusses files. It shows you how to open, read, and write files, how to read from compressed files, how to map files into memory, and so on. The 32bit API contains quite a few interesting file capabilities.
- Chapter 3 introduces the drive structure of Windows. You will learn how to query the drives on your local machine, as well as how to query and connect to drives on the network.
- Chapter 4 discusses the directory structure. It shows you how to create and traverse directory trees.
- Chapter 5 talks about the nextgeneration directory structure of Windows 2000. It shows you how to create and use this new directory capability. It also gives suggestions on when to use this activedirectory capability.
- Chapter 6 offers a complete introduction to processes and threads in the Windows environment. You will see how to multithread your own applications, as well as MFC applications. There is also a discussion of processes, interprocess communication, and inheritance.
- Chapter 7 discusses Windows synchronization mechanisms. Critical sections, mutexes, semaphores and events help you write multithreaded code that does not step on itself. The chapter introduces you to general synchronization principles and bugs, and shows solutions to a number of standard problems. It also shows you how to incorporate synchronization mechanisms into an MFC program without stalling its event loop.
- Chapter 8 talks about network communications. Windows contains two different native technologies for communicating over a network: mailslots and named pipes. Windows also supports UPD and TCP packets on TCP/IP networks. The latter capabilities let you intercommunicate with UNIX and other TCP/IP machines. The chapter includes a complete introduction to network principles and terminology.
- Chapter 9 intoduces Remote Procedure Calls, or RPCs. An RPC lets you make a function call that is transmitted over a network and executed on another machine. This chapter contains a complete introduction to the hows and whys of RPCs, as well as design principles to keep in mind when creating client/server systems with RPCs. It contains examples of auto, implicit, explicit, and context binding, and also shows how to incorporate RPCs into MFC programs.
- Chapter 10 discusses Distributed COM (DCOM). This chapter shows how DCOM objects are created and distributed to create a distributed network.
- Chapter 11 talks about communications ports in Windows systems. It shows you how to access both the serial and parallel ports, and demonstrates a simple terminal emulator and bulletin board system.
- Chapter 12 discusses Windows 2000 services. These are background processes that start at boot time and run regardless of who is logged in, just like daemons in UNIX. This chapter shows you how to create your own services and install them in NT's service manager. It also shows you how to place RPC servers into services so they run continuously.
- Chapter 13 offers a complete introduction to the Windows 2000 security system. This system is uniform across all NT objects, so you will learn how to secure files, registry keys, pipes, semaphores, and so on. It teaches you everything you need to know to create and modify access control lists and security descriptors.
- Chapter 14 discusses consoles, which you will use when you want to create textbased programs in Windows. For example, if you want to create a terminal emulator, consoles offer an easy way to handle the keyboard input and character output for the emulator.
- Chapter 15 talks about Microsoft Management Console (MMC). It will demonstrate the possibilities, and methods for using ATL (Active Template Library) to do Snapins.
- Chapter 16 shows you how to access system information, and how to log users off and shut down or reboot the system. For example, this chapter shows you how to determine how many CPUs a system contains, or how many buttons there are on the mouse.
- Chapter 17 shows you how to modularize your programs using dynamic link libraries (DLLs). Windows can be thought of as an extensible operating system because of DLLs. A programmer can easily add capabilities that others can use by creating a DLL and publishing its interface. Windows itself places much of its functionality in DLLs.
- Chapter 18 discusses some of the basics of the Component Object Model (COM). This will prepare us for the discussion in Chapter 19, of COM+ and Windows 2000.
- Chapter 19 discusses the new COM+ and Windows 2000. This will prepare us for the discussion about Windows 2000 Distributed Network Architecture (DNA), which follows this chapter.
- Chapter 20 discusses Windows 2000 Distributed Network Architecture (DNA). It covers the possibilities and gives a threetiered architecture example.
- Chapter 21 contains short discussions and examples on six miscellaneous topics: the registry, the event log, the Windows time model, error handling, structured exception handling, and the memory model.
- Appendix A shows you how to compile the different types of code found in the book.
- Appendix B contains information on contacting the authors via Email to ask questions and obtain free supplements and updates to this book.
Contacting the Author: Questions, Comments, and Version Changes
One thing about Microsoft is that it never stands still for very long. Its compilers and libraries are constantly changing. One of the goals for this book is that its code be as compatible as possible with existing and future releases of Microsoft compiler products. Another goal is to give you "investmentgrade" knowledgeknowledge that does not lose its value over time, and that is transferable between as many different platforms as possible.
As things change, however, you need a way to get updates and corrections. You may also have questions, comments or suggestions for improving this book. If so, we would like to hear from you. You can use our free Email information server to get updates and supplements to this book. You can also send questions and comments via Email or U.S. mail. Please see Appendix B for instructions.