pcjs/pubs/pc/software/os2/microsoft/ptk10/plguide/chapter1/README.md

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Microsoft OS/2 Programmer's Learning Guide

Introduction

1.1 Overview

The Microsoft® Operating System/2 Programmer's Learning Guide is intended to help the experienced C programmer make the transition to writing programs that use the Microsoft Operating System 2 application programming interface. The guide provides explanations of how to use the MS® OS/2 functions, types, and data structures to carry out useful tasks, and illustrates these explanations with program samples that you can compile and run with MS OS/2.

1.2 What You Need to Start

To start using this guide, you need the following:

• Experience using MS OS/2
• Experience writing C-language programs

The C programming language is the preferred development language for MS OS/2 programs. Many of the programming features of MS OS/2 were designed with C and other high-level languages in mind. MS OS/2 programs can also be developed in Pascal, FORTRAN, BASIC, and assembly language, but C is the most straightforward and easiest language to use to access MS OS/2 functions. For this reason, all program samples in this guide are written in the C programming language.

Before you start any development, you should review the Microsoft Operating System/2 Programmer's Reference. The reference introduces the basic concepts of MS OS/2 and fully defines each MS OS/2 system function. Also, for an explanation of what development tools you need to compile, link, and debug MS OS/2 programs, read the Microsoft Operating System/2 Programming Tools manual.

1.3 What This Guide Covers

This guide shows how to use many features of MS OS/2. In particular, it shows how to do the following:

• Use the file-system functions to open, read from, and write to files.
• Use text-based video-input and -output functions to write text to and control the format of the system screen.
• Use the mouse input functions to read events from the mouse, such as mouse motions and button clicks.
• Use the keyboard-input functions to read characters and keystrokes from the system keyboard.
• Use memory-allocation functions to allocate additional memory for your program.
• Use process-control functions to start child processes and threads.

This guide does not cover some of the advanced features of MS OS/2. For example, it does not show how to use monitors, dynamic linking, queues, subsystem registration, or national-language code-page support. However, there are several MS OS/2 sample programs provided with the MS OS/2 Programmer's Toolkit that do illustrate these features.

1.4 The Lqh Sample Program

This guide shows how to build a sample program similar to the QuickHelp on-line help program provided with the MS OS/2 Programmer's Toolkit. Chapter 7, "Lqh: A Sample Program," contains an overview of the lqh source and an explanation of how the MS OS/2 functions are used in the program.

The lqh source files are provided on disk.

1.5 MS OS/2 Sample Programs

In addition to the lqh program presented in this guide, there are many additional sample program sources on the disks provided with the MS OS/2 Programmer's Toolkit. These small sample programs demonstrate the features of MS OS/2, including features not described in this guide, such as monitors, dynamic linking, queues, and binding.

The following list briefly describes the MS OS/2 sample programs included in the MS OS/2 Programmer's Toolkit:

Program	Description
alloc	Allocates memory (bound).
argument	Passes parameters to threads.
asmexmpl	Creates and manages threads in assembly language.
asyncio	Shows how to use asynchronous input and output functions to write to the screen.
beepc	Beeps the speaker (bound).
config	Displays the machine configuration (bound).
country	Displays the current country information (bound).
critsec	Uses a critical section to prevent conflict between two threads that are using the printf function.
csalias	Creates alias code segments.
cwait	Waits for a child process to exit.
datetime	Prints the date and time (bound).
dosexit	Uses the DosExit function to exit threads.
dynlink	Shows how to create C and assembly-language dynamic­link libraries (bound).
exitlist	Sets up an exit routine and then exits.
fsinfo	Gets and sets volume information for drive A (bound).
getenv	Prints the first element of the environment (bound).
hello	Writes "Hello, world" to the screen (bound).
huge	Allocates "huge" memory (bound).
infoseg	Prints information about a process.
iopl	Gets and displays the current cursor position.
keys	Prints keycodes by using the KbdCharIn function (bound).
kill	Uses the DosKillProcess function to terminate a thread.
machmode	Displays the machine mode (bound).
monitors	Registers and terminates monitors.
move	Moves files (bound).
pipes	Uses pipes.
qhtype	Opens les and prints out handle information (bound).
queues	Uses queues to transfer data between consumer and server processes.
realloc	Increases and decreases the size of a segment.
session	Uses the session-manager functions.
setmaxfh	Sets the maximum number of file handles to 30.
setvec	Modifies the interrupt-vector table (bound).
share	Passes keystrokes between processes that are using shared memory.
signal	Uses a signal handler to catch the CONTROL+C key (bound).
sleep	Sleeps for a while (bound).
suballoc	Uses the suballocation functions (bound).
suspend	Suspends and resumes a thread.
threads	Creates and manages threads.
timer	Sleeps and then beeps three times.
version	Prints the DOS version (bound).
vioreg	Registers a Vio subsystem.

The following sample programs are extended examples that combine many of the features illustrated in the previous samples:

Program	Description
terminal	Emulates a terminal and can be used with a direct connection to a host or through a Hayes modem.
sse	Edits text (bound).
cpgrep	Searches strings, using threads to make the speed of the search as fast possible.
ds	Displays and moves directory trees, and creates and uses an initialization file in the directory specified by the environment variable USER.
filelist	Lists files in a directory (bound).
life	Demonstrates how to use the the mouse interface in a bound program (bound).
mandel	Displays the Mandelbrot set, using EGA high-resolution graphics.
bigben	Displays a digital clock, demonstrating the Vio functions (bound).
setega	Sets 25/43-line mode (bound).
chaser	Demonstrates the use of threads (requires a mouse).

1.6 MS OS/2 and the C Run-time Library

Many of the sample programs included in the MS OS/2 Programmer's Toolkit combine both MS OS/2 and C run-time functions to carry out their tasks. Although you can use C run-time functions in MS OS/2 programs, the program samples in this guide use MS OS/2 functions exclusively.

In general, there are no special restrictions on using C run-time functions, as long as you use the appropriate version of the C run-time library. For more information about using C run-time functions with MS OS/2 programs, see the Microsoft C Optimizing Compiler Version 5.1 Update.