Micro Focus Server Express™

Multi-threaded Programming

Micro Focus™

Issue 2
March 2000

Copyright © 2000 Micro Focus International Limited. All rights reserved.
This document and the proprietary marks and names used herein are protected by international law.

Micro Focus has made every effort to ensure that this book is correct and accurate, but reserves the right to make changes without notice at its sole discretion at any time. The software described in this document is supplied under a license and may be used or copied only in accordance with the terms of such license, and in particular any warranty of fitness of Micro Focus software products for any particular purpose is expressly excluded and in no event will Micro Focus be liable for any consequential loss.

Micro Focus® is a registered trademark, and Micro Focus™, Object COBOL™ and Server Express™ are trademarks, of Micro Focus International Limited.

Preface

This book introduces you to multi-threaded programming on Server Express. It describes in detail thread synchronization and gives information and examples on writing multi-threaded programs.

Audience

This book is for all programmers and system designers using Server Express to create multi-threaded COBOL programs. It assumes you are familiar with the general concepts of business computing, of using UNIX, and of using Server Express.

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Notations and Conventions

Enter refers to the carriage return or Enter key. Where commands to be typed are shown, the Enter key is not explicitly shown; it is treated as implicit that Enter must be pressed at the end of the line.
Hexadecimal numbers are enclosed in quotation marks and preceded by a lower-case "x" or "h"; for example, x"9D", h"03FF". The "x" is used when the hexadecimal number represents a character string; the "h" when it represents a numerical value.
PIC X is used rather than PIC 99 with the COMP-X and COMP-5 data types. Unlike PIC 99, PIC X shows the length of the data item and so demonstrates more clearly the use of COMP-X, which is to define a binary item of the specified number of bytes.
Keytops and menu choices are emboldened within the text.
In some environments, you might notice that what appears on your screen differs in minor ways (for example, version numbers) from that illustrated in this book. This will not affect the operation of your software.
The keys described in this book are not available in all environments. When there is a reference to use of a key such as a status or function key, this refers to the logical press and release of this key, rather than the physical keystroke. If your environment does not support the key given, please consult the Appendix UNIX Key Usage Chart in your Server Express User's Guide for the equivalent key.
The term "window" refers to a delineated area on the screen, normally smaller than the full screen. The term "Windows" refers to Microsoft Windows 3.1 or later.

The notation used to describe the format of command lines is as follows:

Words printed in italics are generic terms representing names to be devised by you.
Material enclosed in square brackets [ ] is optional.
When material is enclosed in braces { }, you must choose from the options within them. If there is only one option in the braces, the braces indicate repetition.
The ellipsis (. . .) follows { } or [ ] and means you can repeat the material in the { } or [ ]. The number of repetitions allowed is unlimited unless otherwise stated. If the ellipsis is used with [ ] the material can be omitted altogether.
If a command line does not fit across the page, it is continued on the next line; the continuation line is indented.
Command line options can be specified as /option or -option.