Order Number: AA--QJRWC--TE

This manual provides information about the Compaq Fortran program development environment on Compaq OpenVMS Alpha systems.

It describes compiling, linking, running, and debugging Compaq Fortran programs. It also describes the run-time environment, including run-time performance, I/O and error-handling support, data types, numeric data conversion, calling other procedures, and compatibility with Compaq Fortran 77.

Revision/Update Information: This manual replaces the previous version, AA--QJRWB--TE.

Software Version: Compaq Fortran for OpenVMS Alpha Systems Version 7.4 or higher

Compaq Computer Corporation

Houston, Texas

© 2001 Compaq Computer Corporation

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This document was prepared using DECdocument, Version V3.3-1e.

Contents

Index

This manual describes the Compaq Fortran compiler command, compiler, and run-time environment. This includes how to compile, link, execute, and debug Compaq Fortran programs on an Alpha system (Alpha processor architecture) running the Compaq OpenVMS Alpha operating system. It also describes performance guidelines, I/O and error-handling support, calling other procedures, and compatibility.

Intended Audience

This manual makes the following assumptions about you, the reader:

• You already have a basic understanding of the Fortran 90/95 language. Tutorial Fortran 90/95 language information is widely available in commercially published books (see the online release notes or the Preface of the Compaq Fortran Language Reference Manual).
• You are familiar with the operating system commands used during program development and a text editor. Such information is available in your operating system documentation set.
• You have access to the Compaq Fortran Language Reference Manual, which describes the Compaq Fortran 90/95 language.

Structure of This Document

This manual consists of the following chapters and appendixes:

• Chapter 1 introduces the programmer to the Compaq Fortran compiler, its components, and related commands.
• Chapter 2 describes the FORTRAN command qualifiers in detail.
• Chapter 3 describes how to link and run a Compaq Fortran program.
• Chapter 4 describes the OpenVMS Debugger and some special considerations involved in debugging Fortran programs. It also lists some relevant programming tools and commands.
• Chapter 5 describes ways to improve run-time performance, including general software environment recommendations, appropriate FORTRAN command qualifiers, data alignment, efficiently performing I/O and array operations, other efficient coding techniques, profiling, and optimization.
• Chapter 6 provides information on Compaq Fortran I/O, including statement forms, file organizations, I/O record formats, file specifications, logical names, access modes, logical unit numbers, and efficient use of I/O.
• Chapter 7 lists run-time messages and describes how to control certain types of I/O errors in your I/O statements.
• Chapter 8 describes the native Fortran OpenVMS Alpha data types, including their numeric ranges, representation, and floating-point exceptional values. It also discusses the intrinsic data types used with numeric data.
• Chapter 9 describes how to access unformatted files containing numeric little endian and big endian data different than the format used in memory.
• Chapter 10 describes how to call routines and pass arguments to them.
• Chapter 11 describes how to utilize OpenVMS Record Management Services (RMS) from a Compaq Fortran program.
• Chapter 12 describes how to access records using indexed sequential access.
• Chapter 13 gives an introduction on how to exchange and share data among both local and remote processes.
• Chapter 14 describes facilities that can be used to handle---in a structured and consistent fashion---special conditions (errors or program-generated status conditions) that occur in large programs with many program units.
• Chapter 15 provides information on the Compaq Extended Math Library (CXML), a comprehensive set of mathematical library routines callable from Fortran and other languages.
• Appendix A describes the compatibility between Compaq Fortran for OpenVMS Alpha systems and Compaq Fortran on other platforms, especially Compaq Fortran 77 for OpenVMS systems.
• Appendix B describes diagnostic messages issued by the Compaq Fortran compiler and lists and describes messages from the Compaq Fortran Run-Time Library (RTL) system.
• Appendix C lists the Compaq Fortran logical names recognized at compile-time and run-time.
• Appendix D identifies the Compaq Fortran include files that define symbols for use in Compaq Fortran programs.
• Appendix E contains examples of the use of a variety of system services.

Associated Documents

The following documents may also be useful to Compaq Fortran programmers:

• Compaq Fortran Language Reference Manual
  Describes the Compaq Fortran 90/95 source language for reference purposes, including the format and use of statements, intrinsic procedures, and other language elements. Compaq Fortran extensions to the appropriate Fortran standard are identified by blue color in the printed and online documents. It also provides an overview of new Fortran 90 and Fortran 95 features (not available in FORTRAN-77). Language differences among Compaq Fortran platforms are identified.
• Compaq Fortran Installation Guide for OpenVMS Alpha Systems
  Explains how to install Compaq Fortran on OpenVMS Alpha systems using POLYCENTER® Software Installation (PCSI) software, including prerequisites and requirements.
• Compaq Fortran online release notes
  Provide the most recent information on this version of Compaq Fortran. You can view or print the ASCII version of the online release notes from:

  SYS$HELP:FORTRAN.RELEASE_NOTES

  
  Other forms of the release notes (PostScript) are also provided, using the file name:

  SYS$HELP:FORTRAN_RELEASE_NOTES.*

• Compaq Fortran online DCL HELP
  Summarizes the Compaq Fortran command-line qualifiers, explains run-time messages, and provides a quick-reference summary of language topics. To use online HELP, type either of the following commands:

  $ HELP FORTRAN

• Operating system documentation
  The operating system documentation set describes the DCL commands (such as LINK), OpenVMS routines (such as system services and run-time library routines), OpenVMS concepts, and other aspects of the programming environment.
  For OpenVMS Alpha systems, sources of programming information include the following:
  • OpenVMS Programming Environment Manual
  • OpenVMS Programming Concepts Manual
  • OpenVMS Programming Interfaces: Calling a System Routine
  • OpenVMS Debugger Manual
  • Alpha Architecture Reference Manual
  • Alpha Architecture Handbook
  
  For information on the documentation for the OpenVMS Alpha operating system, including a list of books in the programmer's kit, see the Overview of OpenVMS Documentation.
  OpenVMS VAX® to OpenVMS Alpha porting information can be found in the Migrating an Application from OpenVMS VAX to OpenVMS Alpha. (For Fortran-specific porting information, see Appendix A.)
  You can also use online DCL HELP for various OpenVMS commands and most routines by typing HELP. For the Debugger (and other tools), type HELP after you invoke the Debugger. For information on operating system messages, use the HELP/MESSAGE command.
  The following Web site contains comprehensive information on OpenVMS Alpha systems: http://www.compaq.com/openvms
• Other layered product documentation
  If you are using a programming-related layered product package from Compaq®, consult the appropriate documentation for the layered product package for use of that product.

Compaq Fortran World Wide Web Pages

If you have Internet access and a World Wide Web (WWW) browser, you are invited to view the Compaq Fortran home page, located at the following URL:

http://www.compaq.com/fortran/

This Web site contains information about software patch kits, example programs, and additional product information.

Sending Compaq Your Comments on This Manual

We welcome your comments on this or any other Compaq Fortran manual. You can send comments by Internet electronic mail to:

fortran@compaq.com

If you have suggestions for improving particular sections or find any errors, please indicate the title, order number, and section numbers. Compaq also welcomes general comments.

Getting Help from Compaq

If you have a customer support contract and have comments or questions about Compaq Fortran software, you can contact the Compaq Customer Support Center (CSC), preferably using electronic means such as DSNlink. In the United States, customers can call the CSC at 1-800-354-9000.

You may also send comments, questions and suggestions about the Compaq Fortran product to the following Internet mail address: fortran@compaq.com. Please note, however, that this address is for informational inquiries only. It is not a formal support channel.

Conventions Used in this Document

This manual uses the conventions shown in Table 1:

Table 1 Conventions Used in This Document

Convention	Meaning
$	This manual uses a dollar sign ($) to represent the user prompt.
[Return]	This symbol indicates that you must press the named key on the keyboard.
Ctrl/ x	This symbol indicates that you must press the Ctrl key while you simultaneously press the key labeled x.
$ FORT _File:	This manual displays system prompts and responses using a monospaced font. Typed user input is displayed in a bold monospaced font.
newterm	Bold type indicates the introduction of a new term in text.
variable	Italic type indicates important information, a complete title of a manual, or variable information, such as user-supplied information in command or option syntax.
	Large braces enclose lists from which you must choose one item. For example: STATUS DISPOSE DISP
[ ]	Square brackets enclose items that are optional. For example: BLOCK DATA [nam]
...	A horizontal ellipsis means that the item preceding the ellipsis can be repeated. For example: s[,s]...
. . .	A vertical ellipsis in a figure or example means that not all of the statements are shown.
real	This term refers to all floating-point intrinsic data types as a group.
complex	This term refers to all complex floating-point intrinsic data types as a group.
logical	This term refers to logical intrinsic data types as a group.
integer	This term refers to integer intrinsic data types as a group.
DECwindows, DECwindows Motif	References to DECwindows or DECwindows Motif refer to DECwindows Motif software.
Fortran	This term refers to language information that is common to ANSI FORTRAN-77, ANSI/ISO Fortran 90, ANSI/ISO Fortran 95, and Compaq Fortran 90.
Fortran 90	This term refers to language information that is common to ANSI/ISO Fortran 90 and Compaq Fortran. For example, a new language feature introduced in the Fortran 90 standard.
Fortran 95	This term refers to language information that is common to ISO Fortran 95 and Compaq Fortran. For example, a new language feature introduced in the Fortran 95 standard.
Compaq Fortran (DEC Fortran 90)	The term Compaq Fortran (formerly DEC Fortran 90 and DIGITAL Fortran 90) refers to language information that is common to the Fortran 90 and 95 standards, and any Compaq Fortran extensions. Since the Fortran 90 standard is a superset of the FORTRAN-77 standard, Compaq Fortran also supports the FORTRAN-77 standard. Compaq Fortran supports all of the deleted features of the Fortran 95 standard.
Compaq Fortran 77 (DEC Fortran)	The term Compaq Fortran 77 (formerly DEC Fortran) refers to language information that is common to the FORTRAN-77 standard and any Compaq Fortran 77 extensions.
VMS®, OpenVMS	References to VMS, VMS system, OpenVMS, or OpenVMS system refer to the OpenVMS operating system.