Table Of ContentThe Fortran 2003 Handbook
· ·
Jeanne C. Adams Walter S. Brainerd
· ·
Richard A. Hendrickson Richard E. Maine
·
Jeanne T. Martin Brian T. Smith
The Fortran 2003 Handbook
The Complete Syntax, Features and Procedures
123
Jeanne C. Adams Walter S. Brainerd
National Center for Atmospheric Research The Fortran Company
Boulder, Colorado, USA Tucson, Arizona, USA
Richard A. Hendrickson Richard E. Maine
Spackman & Hendrickson, Inc. NASA Dryden, Edwards AFB
Minneapolis, Minnesota, USA C alifornia, USA
Jeanne T. Martin, Brian T. Smith
Retired: Lawrence Livermore National University of New Mexico
Security, California, USA Albuquerque, New Mexico, USA
ISBN: 978-1-84628-378-9 e-ISBN: 978-1-84628-746-6
DOI: 10.1007/978-1-84628-746-6
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the British Library
Library of Congress Control Number: 2008934286
© Jeanne C. Adams, Walter S. Brainerd, Richard A. Hendrickson, Richard E. Maine, Jeanne T. Martin and Brian T. Smith 2009
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright,
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Contents
Preface xi
1 Introduction 1
1.1 History 1
1.2 The Fortran 2003 Language Standard 4
1.3 Notation Used in this Book 6
1.4 Approximations to Real and Complex Values 8
1.5 References 8
2 Fortran Concepts and Terms 11
2.1 Program Organization 12
2.2 Data Environment 17
2.3 Program Execution 22
2.4 Terms 24
2.5 High-Level Syntax Forms 30
2.6 Ordering Requirements 39
2.7 Example Fortran Program 40
3 Language Elements and Source Form 43
3.1 The Processor Character Set 44
3.2 Lexical Tokens 47
3.3 Source Form 50
3.4 The INCLUDE Line 58
4 Data Types 61
4.1 Data Type Selection 62
4.2 What Is Meant by “Type” in Fortran? 66
4.3 Intrinsic Types 68
4.4 Derived Types 80
4.5 Array Constructors 111
vi Contents
4.6 Enumerations 113
5 Declarations 115
5.1 Type Declaration Statements 118
5.2 Polymorphism 120
5.3 Implicit Typing 122
5.4 Array Properties 124
5.5 The ALLOCATABLE Attribute 130
5.6 Pointer Properties 131
5.7 Value Definition Properties 133
5.8 Module Entity Properties 144
5.9 Dummy Argument Properties 149
5.10 Procedure Properties 154
5.11 The Procedure Declaration Statement 157
5.12 Attribute Compatibility 159
5.13 The NAMELIST Statement 161
5.14 Storage Association 162
6 Using Data 171
6.1 Constants and Variables 173
6.2 Designators 173
6.3 Type Parameter Inquiry 175
6.4 Substrings 176
6.5 Structure Components 178
6.6 Arrays 180
6.7 Pointers and Allocatable Variables 187
7 Expressions and Assignment 199
7.1 Formation of Expressions 200
7.2 Interpretation of Expressions 206
7.3 Evaluation of Expressions 219
7.4 Special Expressions 223
7.5 Assignment 231
Contents vii
8 Block Constructs and Execution Control 257
8.1 Blocks and Construct Names 258
8.2 The ASSOCIATE Construct 259
8.3 Controlling Execution 261
8.4 The IF Construct and the IF Statement 262
8.5 The CASE Construct 264
8.6 The SELECT TYPE Construct 267
8.7 The DO Construct 271
8.8 Branching 280
8.9 The STOP Statement 284
9 Input and Output Processing 285
9.1 Basic Input/Output Concepts 286
9.2 Input/Output Statement Specifier Lists 299
9.3 The OPEN Statement 309
9.4 Data Transfer Statements 316
9.5 Execution Model for Data Transfer Statements 326
9.6 Error and Other Conditions in Input/Output Statements 340
9.7 The WAIT Statement 343
9.8 The CLOSE Statement 344
9.9 The INQUIRE Statement 346
9.10 File Positioning Statements 357
9.11 The FLUSH Statement 362
9.12 Restrictions on Input/Output Specifiers, List Items, and Statements 363
10 Input and Output Editing 367
10.1 Explicit Formatting 369
10.2 Format Specifications 371
10.3 Formatted Data Transfer 374
10.4 File Positioning by Format Control 379
10.5 Numeric Editing 379
10.6 Logical Editing 392
viii Contents
10.7 Character Editing 393
10.8 Defined Editing 395
10.9 Control Edit Descriptors 395
10.10 List-Directed Formatting 404
10.11 Namelist Formatting 411
11 Program Units 419
11.1 Overview 419
11.2 Fortran Main Program 422
11.3 Modules 423
11.4 External Subprograms 434
11.5 Block Data Program Units 434
12 Using Procedures 437
12.1 Subroutines 438
12.2 Functions 442
12.3 RETURN Statement 447
12.4 Procedure Definition 448
12.5 Procedure Declaration 455
12.6 Argument Association 472
12.7 Special Categories of Procedures 489
12.8 Resolving Procedure References 493
12.9 Procedure Properties 496
13 Intrinsic Procedures and Modules 497
13.1 Properties of Intrinsic Procedures 498
13.2 Representation Models 500
13.3 Intrinsic Procedures 502
13.4 Specific Names for Generic Intrinsic Procedures 512
13.5 Alphabetical List of All Intrinsic Procedures 514
13.6 Standard Intrinsic Modules 514
14 IEEE Exceptions and Arithmetic 521
14.1 Terms and Concepts 522
Contents ix
14.2 IEEE Arithmetic and Exceptions—an Introduction 527
14.3 Descriptions of the Three Intrinsic Modules 534
14.4 Initial and Final Status Requirements Entering and Leaving Any Procedure 551
14.5 Interoperability Issues for IEEE Arithmetic and Exceptions 553
14.6 A Summary of the Optional Features 553
14.7 Examples of the Use of IEEE Features, Arithmetic, and Exceptions Modules 556
15 Interoperability with C 561
15.1 Companion Processors 562
15.2 Binding Labels 562
15.3 The ISO_C_BINDING Intrinsic Module 563
15.4 Interoperability of Types 563
15.5 Interoperation of Data 567
15.6 Interoperation of Procedures 573
15.7 Examples of Interoperation 577
16 Scope, Association, and Definition 581
16.1 Scope 581
16.2 Association 588
16.3 Definition 599
A Standard Intrinsic Procedures 605
B IEEE Module Procedures 667
C Language Evolution 683
C.1 New Features 683
C.2 Obsolescent Features 684
C.3 Deleted Features 685
C.4 Other Compatibility Issues 686
Index of Examples 687
Index 691
Preface
Fortran has been the premier language for scientific computing since its introduction in
1957. Fortran originally was designed to allow programmers to evaluate formu-
las—FORmula TRANslation—easily on large computers. Fortran compilers are now
available on all sizes of machines, from small desktop computers to huge multi-proces-
sors.
The Fortran 2003 Handbook is a definitive and comprehensive guide to Fortran 2003.
Fortran 2003, the latest standard version of Fortran, has many modern features that
will assist the programmer in writing efficient, portable, and maintainable programs
that are useful for everything from “hard science” to text processing.
The Fortran 2003 Handbook is an informal description of Fortran 2003, developed to
provide not only a readable explanation of features, but also some rationale for the in-
clusion of features and their use. In addition, “models” give the reader better insight as
to why the language is the way it is.
Target Audience
This handbook is intended for anyone who wants a comprehensive survey of Fortran
2003, including those familiar with programming language concepts but unfamiliar
with Fortran. Experienced Fortran 95 programmers will be able to use this volume to
assimilate quickly those features in Fortran 2003 that are not in Fortran 95 (Fortran
2003 contains all of the features of Fortran 95).
Although the handbook is written for use in conjunction with the standard, it is
also designed as a practical stand-alone description of Fortran 2003. The syntax rules
have been recast into more readable form. On the other hand, in places where the stan-
dard is not completely clear, a reasonable interpretation is often given, together with
ways to implement and program that will avoid potential problems. Of course, if infor-
mation is being sought to understand a fine point of compiler implementation, settle a
bet, resolve a court case, or determine the answer to a Fortran trivia question, the stan-
dard itself should be considered the final authority.
Organization
Chapters 1–16 correspond to Sections 1–16 in the standard. (The standard is the com-
plete official description of the language, but it is written in a legally airtight, formal
style without tutorial material and can be difficult to understand in places.) The hand-
book and the standard can be read in parallel for insights into the Fortran language.
This makes it feasible to use this handbook to “decipher” the standard, and this is an
ideal use of this book.
xii Preface
Specific information can be found in the following places:
•
A brief list of references can be found at the end of Chapter 1.
•
Each chapter begins with a summary of the main terms and concepts described in
the chapter.
•
Each of the standard intrinsic procedures is described in detail in Appendix A; a
general discussion of the intrinsic functions is in Chapter 13.
•
The IEEE module procedures are described in detail in Appendix B and Chapter
14.
•
Appendix C contains a listing of the new, obsolescent, and deleted features.
•
The index is unusually comprehensive.
Style of the Programming Examples
In order to illustrate many features of the language and as many uses of these features
as possible, no single particular style has been used when writing the examples. In
many cases, the style illustrated is not necessarily one that the authors recommend.
Jeanne Adams
It is with deep regret that we acknowledge the passing in 2007 April of Jeanne Ad-
ams—our coauthor and longtime colleague and friend. Among her many contributions
to computing and Fortran standardization, she is best known for her chairmanship of
the committee that developed Fortran 90.
Walter S. Brainerd
Richard A. Hendrickson
Richard E. Maine
Jeanne T. Martin
Brian T. Smith
USA, 2008 May
