HP OpenVMS Systems

BASIC

Compaq BASIC for OpenVMS
Alpha and VAX Systems

User Manual

Order Number: AA--HY15E--TK

April 2000

This manual describes how to develop Compaq BASIC programs and use Compaq BASIC features on OpenVMS systems.

Revision/Update Information: This revised manual supersedes the DEC BASIC and VAX BASIC for OpenVMS Systems User's Manual.

Software Version: Compaq BASIC Version 1.4
for OpenVMS Alpha Systems
Compaq BASIC Version 3.8
for OpenVMS VAX Systems

Operating System and Version: OpenVMS Alpha Version 7.1 or higher
(with IEEE floating-point support);
OpenVMS Alpha Version 6.1 or higher
(without IEEE floating-point support); or
OpenVMS VAX Version 5.5-2 or higher

Compaq Computer Corporation
Houston, Texas

COMPAQ, VAX, VMS, the Compaq logo, and the DIGITAL logo Registered in U.S. Patent and Trademark Office.

Alpha, DEC BASIC, OpenVMS, and VAX BASIC are trademarks of Compaq Information Technologies Group, L.P.

Motif is a trademark of The Open Group.

All other product names mentioned herein may be the trademarks or registered trademarks of their respective companies.

Confidential computer software. Valid license from Compaq or authorized sublicensor required for possession, use, or copying. Consistent with FAR 12.211 and 12.212, Commercial Computer Software, Computer Software Documentation, and Technical Data for Commercial Items are licensed to the U.S. Government under vendor's standard commercial license.

Compaq shall not be liable for technical or editorial errors or omissions contained herein.

The information in this publication is subject to change without notice and is provided "AS IS" WITHOUT WARRANTY OF ANY KIND. THE ENTIRE RISK ARISING OUT OF THE USE OF THIS INFORMATION REMAINS WITH RECIPIENT. IN NO EVENT SHALL COMPAQ BE LIABLE FOR ANY DIRECT, CONSEQUENTIAL, INCIDENTAL, SPECIAL, PUNITIVE, OR OTHER DAMAGES WHATSOEVER (INCLUDING WITHOUT LIMITATION, DAMAGES FOR LOSS OF BUSINESS PROFITS, BUSINESS INTERRUPTION, OR LOSS OF BUSINESS INFORMATION), EVEN IF COMPAQ HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. THE FOREGOING SHALL APPLY REGARDLESS OF THE NEGLIGENCE OR OTHER FAULT OF EITHER PARTY AND REGARDLESS OF WHETHER SUCH LIABILITY SOUNDS IN CONTRACT, NEGLIGENCE, TORT, OR ANY OTHER THEORY OF LEGAL LIABILITY, AND NOTWITHSTANDING ANY FAILURE OF ESSENTIAL PURPOSE OF ANY LIMITED REMEDY.

The limited warranties for Compaq products are exclusively set forth in the documentation accompanying such products. Nothing herein should be construed as constituting a further or additional warranty.

ZK5424

The Compaq OpenVMS documentation set is available on CD-ROM.

Contents

Index

Preface

Compaq BASIC for OpenVMS Alpha is the new name for DEC BASIC. Compaq BASIC for OpenVMS VAX is the new name for VAX BASIC. Any references to the former names in product documentation or other components should be construed as references to the Compaq BASIC names. Any references to BASIC or to Compaq BASIC apply to both products unless otherwise specified. References to Alpha BASIC mean Compaq BASIC for OpenVMS Alpha, and references to VAX BASIC mean Compaq BASIC for OpenVMS VAX.

This manual describes how to develop and use BASIC programs on OpenVMS systems and describes BASIC language features.

Intended Audience

This manual is intended for programmers who compile, link, and execute BASIC programs on OpenVMS systems. Users should have a working knowledge of BASIC or another high-level programming language, the Digital Command Language (DCL), and DCL command procedures.

Document Structure

This manual contains the following chapters and appendixes:

Part 1 Developing BASIC Programs on OpenVMS Systems

Chapter 1 provides a brief overview of BASIC.
Chapter 2 describes how to develop programs in the VAX BASIC Environment (VAX BASIC only).
Chapter 3 describes how to develop programs at DCL command level and how to generate a compiler listing.
Chapter 4 describes how to use the OpenVMS Debugger to debug BASIC programs.

Part 2 BASIC Programming Concepts

Chapter 5 explains how to get started with BASIC.
Chapter 6 explains simple input and output procedures.
Chapter 7 shows how to use arrays.
Chapter 8 explains data definitions.
Chapter 9 explains how to create user-defined data structures with the RECORD statement.
Chapter 10 shows how to control the flow of program execution.
Chapter 11 explains how to use functions.
Chapter 12 explains how to handle strings.
Chapter 13 describes structured programming techniques.
Chapter 14 explains how to manage files.
Chapter 15 describes how to format output with the PRINT USING statement.
Chapter 16 explains error-handling techniques.
Chapter 17 shows how to use compiler directives.
Chapter 18 describes how BASIC represents data.

Part 3 Using BASIC Features on OpenVMS Systems

Chapter 19 describes additional I/O considerations on OpenVMS systems.
Chapter 20 describes OpenVMS System Services and Run-Time Library routines.
Chapter 21 describes the use of user-supplied libraries and shareable images.
Chapter 22 describes how to use CDD/Repository capabilities.
Chapter 23 describes using standard Motif Bindings with BASIC.

Appendixes

Appendix A lists compile-time error messages.
Appendix B lists run-time error messages.
Appendix C provides an overview of the optional productivity tools.

Platform Labels

A platform is a combination of operating system and central processing unit (CPU) that provides a distinct environment in which to use a product (in this case, a language). This manual contains information for the following language platforms:

OpenVMS Alpha
OpenVMS VAX

Information in this manual applies to both supported platforms, unless it is otherwise noted. Platform-specific information is noted in the manual as follows:

Alpha BASIC refers to information that is correct for Compaq BASIC for OpenVMS Alpha systems.
VAX BASIC refers to information that is correct for Compaq BASIC for OpenVMS VAX systems.

Reader's Comments

Compaq welcomes your comments on this manual. Please send comments to either of the following addresses:

Internet
Mail	Compaq Computer Corporation OSSG Documentation Group, ZKO3-4/U08 110 Spit Brook Rd. Nashua, NH 03062-2698

How to Order Additional Documentation

If you have access to the World Wide Web, please visit our website at

  http://h71000.www7.hp.com/commercial/basic/basic_index.html

Click Software Product Description, and read the ordering information. Note the order numbers of the documents you want. For pricing and further information, call 1--800--282-6672.

Use the following World Wide Web address for information about how to order OpenVMS operating system documentation:

http://www.compaq.com/

If you need help deciding which documentation best meets your needs, call 1--800--282--6672.

Conventions

In this manual, every use of the name Compaq BASIC or the name BASIC applies to both Compaq BASIC for OpenVMS Alpha and Compaq BASIC for OpenVMS VAX software.

Table 1 shows the conventions used in this manual.

**Table 1 Conventions Used in This Manual**
Convention	Description
$	A dollar sign ($) represents the OpenVMS DCL system prompt.
`[Return]`	In examples, a key name enclosed in a box indicates that you press that key on the keyboard. (In text, a key name is not enclosed in a box.) In the HTML version of this document, this convention appears as brackets, rather than a box.
Ctrl/ x	The key combination Ctrl/ x indicates that you must hold down the key labeled Ctrl while you press another key, for example Ctrl/Y or Ctrl/Z.
KP n	The phrase KP n indicates that you must press the key labeled with the number or character n on the numeric keypad, for example, KP3 or KP-.
PF1 x	A sequence such as PF1 x indicates that you must first press and release the key labeled PF1, then press and release another key.
n	A lowercase italic n indicates the generic use of a number.
...	A horizontal ellipsis in examples indicates one of the following possibilities: Additional optional arguments in a statement have been omitted. The preceding item or items can be repeated one or more times. Additional parameters, values, or other information can be entered.
. . .	A vertical ellipsis indicates the omission of items from a code example or command format; the items are omitted because they are not important to the topic being discussed.
()	In format descriptions, parentheses indicate that you must enclose the options in parentheses if you choose more than one.
[]	In format descriptions, brackets indicate optional elements; you can select none, one, or all of the elements.
{ }	In format descriptions, braces indicate that one element in a list is required. You must choose one and only one from the list.
boldface text	Boldface text is used for the introduction of a new term.
italic text	Italic text represents parameters, arguments, and information that can vary in system messages (for example, Internal error number), as well as book titles and emphasized information.
UPPERCASE	Uppercase indicates the name of a command, routine, file, or file protection code, or the abbreviation for a system privilege.

Table 2 defines mnemonics and other terms used in the syntax diagrams.

**Table 2 Mnemonics and Other Terms Used in Syntax**
Term	Meaning
angle	Angle in radians or degrees
array	Array; syntax rules specify whether the bounds or dimensions can be specified
chnl	I/O channel associated with a file
chnl-exp	Numeric expression that specifies a channel number
com	Specific to a COMMON block
cond	Conditional expression; indicates that an expression can be either logical or relational
cond-exp	Conditional expression
const	Constant value
data-type	Data type keyword
decimal-var	Decimal variable
decl-item	Array, record, or variable
def	Specific to a DEF function
delim	Delimiter
equiv-name	File specification, device, or logical name to be assigned a logical name
err-num	Run-time error number
exp	Expression
ext-routine	External function
external-param	External parameter
file-spec	File specification
func	Specific to a FUNCTION subprogram
int	Integer value
int-const	Integer constant
int-exp	Expression that represents an integer value
int-var	Variable that contains an integer value
label	Alphanumeric statement label
lex	Lexical; used to indicate a component of a compiler directive
lex-exp	Lexical expression
lex-var	Lexical variable
line	Statement line; may or may not be numbered
line-num	Statement line number
lit	Literal value, in quotation marks
log-exp	Logical expression
log-name	1- to 63-character logical name to be associated with equiv-name
macro-id	User identifier following the rules for BASIC identifiers
map	Specific to a MAP statement
matrix	Two-dimensional array
name	Name or identifier; indicates the declaration of a name or the name of a BASIC structure, such as a SUB subprogram
num	Numeric value
num-lit	Numeric literal
param-list	Parameter list, such as for a SUB subprogram
pass-mech	Valid BASIC passing mechanism
prog-name	Program name
real	Floating-point value
real-exp	Real expression
real-var	Real variable
rel-exp	Relational expression
relationship-type	Oracle CDD/Repository protocol
replacement-token	Identifier, keyword, compiler directive, literal constant, or operator
routine	SUB subprogram or other callable procedure
str	Character string
str-exp	Expression that represents a character string
str-lit	String literal
str-var	Variable that contains a character string
sub	Specific to a SUB subprogram
target	Target point of a branch statement; either a line number or a label
unq-str	Unique string
unsubs-var	Unsubscripted variable, as opposed to an array element
var	Variable