ISO/IEC 1539:1991

Information technology - Programming languages - FORTRAN (Available in electronic form)

Technologies de l'information — Langages de programmation — FORTRAN

General Information

• Status: Withdrawn
• Publication Date: 03-Jul-1991
• Withdrawal Date: 03-Jul-1991
• ICS: 35.060 - Languages used in information technology
• Technical Committee: ISO/IEC JTC 1/SC 22 - Programming languages, their environments and system software interfaces
• Drafting Committee: ISO/IEC JTC 1/SC 22/WG 5 - Fortran
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 03-Dec-1997
• Completion Date: 30-Oct-2025

Relations

• Consolidated By: ISO 12162:1995 - Thermoplastics materials for pipes and fittings for pressure applications - Classification and designation - Overall service (design) coefficient
• Effective Date: 06-Jun-2022
• Revised: ISO/IEC 1539-1:1997 - Information technology - Programming languages - Fortran - Part 1: Base language
• Effective Date: 15-Apr-2008
• Revises: ISO 1539:1980 - Programming languages - FORTRAN
• Effective Date: 15-Apr-2008

Standards Content (Sample)

I NTER NATIONAL
ISOIIEC
STANDARD
Second edition
1991 -07-01
Information technology - Programming
languages - Fortran
Technologies de ïinformation - Langages de programmation - Fortran
Reference number
ISO/IEC 1539 : 1991 (E)
ISO/IEC 1539 : 1991 (E)
Contents
xii
Foreword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1. Overview . . . 1
Scope . 1
1.1
Processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2
1.3 Inclusions and exclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.3.1 1
1.3.2 . 1
1.4 Conformance . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.4.1 3
Notation used in this International Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.5
1.5.1 Syntax rules .
1.5.2 Assumed syntax rules. 4
1.5.3 syntax conventions an . 5
1.5.4 Text conventions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.6 Deleted and obsolescent features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.6.1 Nature of deleted features . 5
1.6.2 Nature of obsolescent features . 5
1.7 Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.8 Normative references. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . tJ
2. Fortran terms and concepts . 7
7,
High level syntax
2.1
2.2 Program unit con
2.2.1 Executable program . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.2.2 Main program . . . . . . . . . . 10
2.2.3 Procedure 10
2.2.4 Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3 Execution concepts. . . . . . . . . . . . . . . . . 11
2.3.1 Executable/nonexecu ta temen t s. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II
2.3.2 Statement order . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.3.3 The END statement 12
2.3.4 Execution sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
d
2.4 Data concepts . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.4.1 Data type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . , . . . , . . . , . . 13
2.4.2 Data value . 13
2.4.3 Data entity . 13
2.4.4 Scalar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.4.5 Array . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.4.6 Pointer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.4.7 Storage 15
2.5 Fundamental terms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.5.1 Name and designator . 15
2.5.2 Keyword . . . . . . . .
0 ISO/IEC 1991
All rights reserved. No part of this publication may be reproduced or utilized in any form or by
any means, electronic or mechanical, including photocopying and microfilm, without permission
in writing from the publisher.
ISO/IEC Copyright Office 0 Case postale 56 0 CH-121 1 Genève 20 0 Switzerland
Printed in Switzerland
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ISO/IEC 1539 : 1991 (E)
2.5.3 Declara tion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5.4 Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5.5 Reference. . . . . . 16
2.5.6 . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.5.7 Intrinsic . . . . . . . . . . . . . . . . .
2.5.8 Operator . . 16
2.5.9 17
Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Characters, lexical tokens, and source form . 18
3.
3.1 Processor character set . .
.... 18
3.1.1 Letters . . .
3.1.2 Digits .
3.1.3 Underscore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1.4 Special characters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3.1.5 Other characters . . . . . . . 19
3.2 Low-level syntax . .
3.2.1 Keywords . . , . . . . 19
3.2.2 . , . 19
3.2.3 . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.2.4 Operators . . . . . . . . . 20
3.2.5 Statement labels . . . . . . . . . . . 21
3.2.6 Delimiters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.3 Source form . . .
3.3.1 Free source form . 22
3.3.2 Fixed source form . . .
3.4 Including source text .
Intrinsic and derived data types . 25
4.
4.1 The concept of data type . . 25
4.1.1 Set of values . . . . . , ,. , . . 25
4.1.2 Constants .
................ 25
4.1.3 Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4.2 Relationship of types an f. . . . . 26
4.3.2 Nonnumeric types . . . . . . . . . . . . . . . . . . . . . . . . . 30
4.4 Derived types . 32
................. 32
4.4.2 Determination of derived types . . 35
4.4.3 Derived-type values 36
4.4.5 Derived-type operations and assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
4.5 Construction of array values .
I
Data object declarations and specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
5.
I
5.1 Type declaration statements . .
Type specifiers. . . . . . . . . . . . . . . . . . . . . . . 41
5.1.1 .
I
5.1.2 Attributes . . . . . . . . . . . . . , . 43
5.2 Attribute specification statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 I
5.2.1 INTENT statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
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............ 49
5.2.2 OPTIONAL statement . . . . . . . . . . . . . . . .
5.2.3 Accessibility statements . . . . . . . . . . 49
5.2.4 SAVE statement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
5.2.5 DIMENSION statement . . 50
5.2.6 ALLOCATABLE statem . .
5.2.7 POINTER statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2.8 TARGET statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5.2.9 DATA statement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5.2.10 PARAMETER statement . . . . . . . . . . . . . . . . . . . . . .
IMPLICIT statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
5.3
........... 56
5.5 Storage association of data
.................................. 58
Use of data objects . 61
6.
6.1 scalars . . .
...........
6.1.1 Substrings. . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
6.1.2 Structure components . . . . . . . . . . . . . . . . . . . . . . 62
Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
6.2
6.2.1 Whole arrays . . 63
6.2.2 Array elements and array sections . . 63
..
Dynamic association . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
6.3
6.3.1 ALLOCATE statement . . . . . . . . . . . . . . . .
NULLIFY statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
6.3.2
6.3.3 DEALLOCATE statement
7. Expressions and assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
......................................... <...............
7.1.2 Intrinsic operations . . . . . . 74
7.1.3 Defined operations . . .
7.1.4 Data t . 75
................... 77
........... 79
Evaluation of operations . . . . . . . . .
7.1.7
7.2 Interpretation of intrinsic operations . 83
.........I. 84
7.2.3 Relational intrinsic operations . 85
Logical intrinsic operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.2.4
........... 86
Interpretation of defined operations. . . . . . . . . . . . . . . . . . . . . . .
7.3
7.3.1 Unary defined operation .
7.4 Precedence of operators . . 87
.................................... 89
Assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.5
Assignment statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7.5.1
........... 92
7.5.2 Pointer assignment . . . . . . . . . . . . . .
7.5.3 Masked array assignment-W
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ISOAEC 1539 : 1991 (E)
Execution control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.
Executable constructs containing blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
8.1
8.1.1 Rules governing blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
8.1.2 IF construct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8.1.3 CASE construct
8.1.4 DO construct .
8.2 Branching . .
8.2.1 Statement labels . , .
8.2.2 GO TO statement .
8.2.3 Computed GO TO statement .
8.2.4 ASSIGN and assigned GO TO statement . . 107
8.2.5 Arithmetic IF statement . . . . . . . . . . . . . . . . . . . . . . . . 108
8.3 CONTINUE statement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 O8
8.4 STOP statement . .
8.5 PAUSE statement . . , .
9. Input/output statements . . . . . . . . . . . . . . . . . . . .
9.1 Records . .
‘L
cord . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.1.1
9.1.2 Unformatted record . 109
9.1.3 Endfile record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.................... 110
9.2.1 External files . . .
..........................................................
9.3 File connection
........................................... 114
9.3.1 Unit existence . . . . . . . . . . . . . . . .
............................ 115
9.3.3 Preconnect ion. . . . . . . . . . . . . . . . . . . . . . . . . .
9.3.4 The OPEN statement . .
Data transfer statements .
9.4
.................... ...................... 119
9.4.2 Data transfer
................... 124
9.4.6 Termination of data transfer statements . .
........................................
File positioning statements. . . . . . . . . . . . . . .
9.5
9.5.1 BACKSPACE statement .
.............................. 129
ENDFILE statement . . . . . . . . . . . . . . . . . . . . . . . . .
9.5.2
............................ 129
9.5.3 REWIND statement . ._. .
9.6 File inquiry . . . .
...................... 130
9.6.1 Inquiry specifiers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.6.2 Restrictions on inquiry specifiers .
9.6.3 Inquire by output list . . 134
9.7 Restrictions on function references and list items . 134
..................... 134
9.8 Restriction on input/output statements. . . . . . . . . . . . . . . . . . . .
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Input /output editing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.1 Explicit format specification methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
ïO.1.1 FORMAT statement . .
Character format specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
10.1.2
................................. 136
10.2 Form of a format item list . . . .
Edit descriptors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
10.2.1
Fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
10.2.2
Interaction between input
10.3
10.4 Positioning by format control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.5 Data edit descriptors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Numeric editing . . . . . . . . . . . . . . . . . . 139
10.5.1
10.5.2 Logical editing .
Character editing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.5.3
10.5.4 Generalized ed .
10.6 Control edit descriptors . .
10.6.1 Position editin
10.6.2 Slash editing . . 146
10.6.3 Colon editing . . . , , . . , . . . . . . . . . . . . . . . , . . . . . . . . . . __. . . . . . . . . . . . . .
S, SP, and SS editing . 146
10.6.4
10.6.5 P editing . .
BN and BZ editing .
10.6.6
10.7 Character string edit descri
10.7.1 Character const
10.7.2 H editing . .
List-directed formatting. . . 148
10.8
10.8.1 List-directed in
10.3.2 List-directed O 150
10.9 Namelist formatting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
10.9.1 Namelist inpu
10.9.2 Namelist output .
Program units. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.1 Main program . . . . 156
11.1.1 Main program specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.1.2 Main program executable part .
11.1.3 Main program internal procedures . 157
11.2 External subprograms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.3 Modules . . . . 157
11.3.1 Module reference . 157
11.3.2 The USE statemen association . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
11.3.3 Examples of the use of modules . .
11.4 Block data program units . . 161
Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
12.1 Procedure classifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
12.1.1 Procedure classification by reference . . . . . . . . . . .
12.1.2 Procedure classification by means of defi
12.2 Characteristics of procedures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . . . . . . . . . . . . . . . . . . . . . . . . . 165
12.2.1 Characteristics of dummy arguments. . . . . . . . . . . . . . . . . . . . . 165
12.2.2 Characteristics of function results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , . . 166
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12.3 Procedure interface . . 166
12.3.1 Implicit a terfaces . . 166
12.3.2 Specification of the procedure interfac .
12.4 Procedure reference . . . 171
12.4.1 Actual argument li . 171
12.4.2 Function reference .
12.4.3 Elemental intrinsic function reference . 174
12.4.4 Subroutine reference . . 174
12.4.5 Elemental intrinsic subroutine reference . 175
12.5 Procedure definition . . 175
12.5.1 Intrinsic procedure definition . . 175
12.5.2 Procedures defined by subprograms . 175
12.5.3 Definition of procedures by means other than Fortran .
12.5.4 Statement function .
13 .
. Intrinsic procedures 183
Intrinsic functions .
13.1 . 183
13.2 Elemental intrinsic procedures . . 183
U,
13.2.1 Elemental intrinsic function arg nts and results .
Elemental intrinsic subroutine arguments . .
13.2.2 183
13.3 Positional arguments or argument keywords . . 183
Argument presence inquiry function .
13.4 184
13.5 Numeric, mathematical. character. kind. logical. and bit procedures 184
13.5.1 Numeric functions . .
13.5.2 Mathematical functions . .
13.5.3 Character functions .
13.5.4 Character inquiry function . .
13.5.5 Kind functions .
13.5.6 Logical function .
13.5.7 Bit manipulation and inquiry procedures . 184
13.6 Transfer function . . 185
13.7 Numeric manipulation and inquiry functions . . 185
13.7.1 Models for integer and real data . .
13.7.2 Numeric inquiry functions .
........................................... 186
13.7.3 Floating point manipulation functions
Array intrinsic functions . 186
13.8
13.8.1 The shape of array arguments . .
13.8.2 Mask arguments .
Vector and matrix multiplication functions . 186
13.8.3
13.8.4 Array reduction functions . 187
13.8.5 Array inquiry functions . . 187
13.8.6 Array construction functions . 187
13.8.7 Array reshape function . . .
13.8.8 Array manipulation functions .
13.8.9 Array location functions . .
13.8.10 Pointer association status inquiry functions . 187
13.9 Intrinsic subroutines . . 187
13.9.1 Date and ti broutines .
13.9.2 Pseudorandom numbers .
............ 188
13.9.3 Bit copy subroutine . .
vii
ISO/IEC 1539 : 1991 (E)
13.10 Generic intrinsic functions .
13.10.1 Argument presence inquiry function .
13.10.2 Numeric functions .
13.10.3 Mathematical functions .
Character functions . . . . 189
13.10.4
13.10.5 Character inquiry function .
13.10.6 Kind functions .
13.10.7 Logical function .
13.10.8 Numeric inquiry functions . 190
13.10.9 Bit inquiry function .
Bit manipulation functions . . 190
13.10.10
13.10.11 Transfer function . . 190
Floating-point manip tion functions . 190
13.10.12
Vector and matrix multiply functions . . 191
13.10.13
Array reduction functions . 191
13.10.14
13.10.15 Array inquiry functions .
13.10.16 Array construction functions .
13.10.17 Array reshape function . .
13.10.18 Array manipulation functions . 192 .
Array location functions . . 192
13.10.19
Pointer association status inquiry function . 192
13.10.20
13.11 Intrinsic subroutines .
13.12 specific names for intrinsic functions .
13.13 Specifications of the intrinsic procedures . 194
Scope. association. and definition . 241
14 .
Scope of names . . 241
14.1
14.1.1 Global entities . . 241
14.1.2 Local entities . 241
14.1.3 statement entities .
14.2 Scope of labels .
14.3 Scope of external input/
14.4 Scope of operators .
Scope of the assignment symbol . 245
14.5
14.6 Association . .
14.6.1 Name asso
14.6.2 Pointer ass . 246
14.6.3 Storage association .
14.7 Definition and undefinition of variables .
14.7.1 Definition of objects and subobjects . . 249
14.7.2 Variables that are always defined .
Variables that are initially defined . 249
14.7.3
14.7.4 Variables that are initially undefined . . 250
14.7.5 Events that cause variables to become defined .
14.7.6 Events that cause variables to become undefined .
14.8 Allocation status .
viii
ISOAEC 1539 : 1991 (E)
Annexes
A. Glossary of technical terms .
B. Decremental features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B.1 Deleted features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
B.2 Obsolescent features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262
B.2.1 Alternate return . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B.2.2 PAUSE statement . . . . . . 263
B.2.3 ASSIGN and assigned . 263
8.2.4 Assigned FORMAT specifiers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
B.2.5 H editing . 263
C. Section notes . 264
c.1 Section 1 notes . 264
c.1.1 Conformance (1.4) . . . . . . . 264
L
c.2 Section 2 notes . 264
C.2.1 Keywords 264
c.3 Section 3 notes . 264
............................... 264
C.3.2 Comment lines (3.3.1.1, 3.3.2.1) . 264
C.3.3 Statement labels (3.2.5) . 265
C.3.4 Source form (3.3) 265
c.4 Section 4 notes . 265
C.4.1 Zero (4.3.1) .
C.4.2 Characters ( . . . . . . . . 265
C.4.3 Intrinsic and derived data types (4.3, 4.4) . 266
C.4.4 Selection of the approximation methods . . . . . . . . . . . . . . . . . 266
C.4.5 Storage of derived types (4.4.1) 267
c.4.6 Pointers .
c.5 Section 5 notes .
c.5.l Type declaration statements (5.1) 268
C.5.2 The POINTER attribute (5.1.2.7) . 268
C.5.3 The TARGET attribute (5.1.2.8) . . . . . . . . . . 269
C.5.4 PARAMETER statements and IMPLICIT NONE (5.2.10, 5.3) . 2 70
L
C.5.5 EQUIVALENCE statement extensions (5.5.1) . . 2 70
c.5.6 COMMON statement extensions (5.5.2) 2 70
c.6 section 6 notes . 2 70
C.6.1 Substrings (6.1.1) . 270
C.6.2 Array element references . 2 70
C.6.3 Structure components (6.1.2) 2 70
C.6.4 Pointer allocation 271
c.7 2 72
Section 7 notes .
C.7.1 Character assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 72
C.7.2 Evaluation of function references . 2 72
C.7.3 Pointers in expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 72
C.7.4 Pointers on the left side of an assignment .
C.8 Section 8 notes . 2 73
C.8.1 Loop control . . 273
ix
ISOAEC 1539 : 1991 (E)
C.8.2 The CASE construct . .
2 74
C.8.3 Examples of invalid DO constructs .
Section 9 notes . . .
c.9
C.9.1 Input/out .
C.9.2 Files (9.2) . . 275
C.9.3 OPEN stat .
2 76
c.9.4 Connection properties (9.3.2) . . . . . . . . . .
C.9.5 CLOSE statement (9.3.5) . .
2 79
C.9.6 INQUIRE stateme .
Keyword specifiers . . . . . . . . . . . . . 280
C.9.7
Format specifications (9.4.1.1) . . 280
C.9.8
Unformatted input/output (9.4.4.4.1) . . 280
C.9.9
Input/output restrictions . . . . . . . . . . . . . . . . . . . . . .
C.9.10 . 280
C.9.11 Pointers in an input/output list . .
C.9.12 Derived type objects in an inp 280
Section 10 notes . .
............. 281
c.10
Character constant format specification (10.1.2, 10.7.1) . . 281
C.10.1
C.iO.2 T edit descriptor (10.6.1.1). .
C.10.3 Length of formatted records . .
Number of records (10.3, 10.4, 10.6.2) .
c.10.4 281
List-directed input/output (10.8) . . . . . . . . . . . . .
C.iO.5 282
C.10.6 List-directed input (10.8.1) . .
Namelist list items for character input (10.9.1.3) .
C.10.7 282
C.î0.8 Namelist output records (10.9.2.2) . .
c.11 Section il notes . 283
C.iî.1 Main program and block d 283
C.ïi.2 Dependent compilation (11 .
C.11.3 Pointers in modules _._. .
c.11.4 Example of a module (11.3) . .
c.12 Section 12 notes . 288
C.12.1 Examples of host association (12.1.2.2.1) . 288
C.12.2 External procedures (12.3.2.2) . . .
c.12.3 Procedures defined by mea 289
C.12.4 Procedure interfaces (12.3) .
C.12.5 Argument association and 290
C.12.6 Argument intent specificati
Dummy argument restrictions (12.5.2.9) .
C.12.7 291
C.12.8 Pointers and targets as arguments . 291
C.12.9 The ASSOCIATED functi 292
C.12.10 Internal procedure restrictions . . . . . . . . . . 292
C.12.11 The result variable (12.5.2.2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
Section 13 notes . . .
C.13 293
C.13.1 Summary O .
C.13.2 Examples . . . .
............ 295
c.13.3 FORmula TRANslation and array processing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299
C.13.4 Sum of squared residuals . . 300
Vector norms: infinity-norm and one-norm . . . . . . . . . . . . . . .
c.13.5 . 300
C.13.6 Matrix norms: infinity-norm and one-norm . 300
c.13.7 Logical queries. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 300
C.13.8 Parallel computations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
c.13.9 Example of element-by-element computation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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ISO/IEC 1539 : 1991 (E)
C.13.10 Bit manipulation and inquiry procedures .
C.14 Section 14 notes . .
c.14.1 Storage association of zero-sized objects .
D . Syntax rules .
D.1 Syntax rules and constraints . . 303
D.l.l Overview . .
D.i.2 Fortran terms and concepts .
D.1.3 Characters, lexical tokens, and source form . .
D.1.4 Intrinsic and derived data types .
D.1.5 Data object declarations and specifications . 310
D.1.6 Use of data objects . 315
D.1.7 Expressions and assignment . .
D.1.8 Execution control
D.1.9 Input/output statements .
D.ï.10 Input/output editing . 326
D.ï.11 Program units . . 328
D.1.12 Procedures .
D.1.13 Intrinsic procedures . 331
D.1.14 Scope, association, and definition 332
D.2 Cross references . 332
D.2.1 Nonterminal symbols that are defined . 332
D.2.2 Nonterminal symbols that are not defined . 338
D.2.3 Terminal symbols . 339
Permuted index for headings . 344
E .
F . Index . 363
Figures
Figure 2.1 Requirements on statement ordering . 11
Table 2.1 Statements allowed in scoping units . 12
Special characters . 19
Table 3.1
Subscript order valu . 65
Table 6.1
Table 7.1 Type of operands a
Interpretation of the numeric intrinsic operators . 84
Table 7.2
Interpretation of the character intrinsic operator // . 84
Table 7.3
Table 7.4 Interpretation of the relational intrinsic operators .
Table 7.5 Interpretation of the logical intrinsic operators .
Table 7.6 The values of operations involving logical intrinsic operators .
Table 7.7 Categories of operations and relative precedences . 87
Table 7.8 Type conformance for the intrinsic assignment statement variable = expr . 89
Table 7.9 Numeric conversion and assignment statement uauiable = expr 90
Values assigned to INQUIRE specifier variables . 279
Table C.1
xi
ISOAEC 1539 : 1991 (E)
Foreword
IS0 (the International Organization for Standardization) and IEC (the International
Electrotechnical Commission) form the specialized system for worldwide standardiz-
ation. National bodies that are members of IS0 or IEC participate in the development
of International Standards through technical committees established by the respective
organization to deal with particular fields of technical activity. IS0 and IEC technical
committees collaborate in fields of mutual interest. Other international organizations,
governmental and non-governmental, in liaison with IS0 and IEC, also take part in the
work.
In the field of information technology, IS0 and IEC have established a joint technical
committee, ISOAEC JTC 1. Draft International Standards adopted by the joint
technical committee are circulated to national bodies for voting. Publication as an
International Standard requires approval by at least 75 Vo of the national bodies
casting a vote.
International Standard ISOAEC 1539 was prepared by Joint Technical Committee
ISOAEC JTC 1, Information technology.
This second edition cancels and replaces the first edition (IS0 1539 : 1980), which has
been technically revised.
Annexes A, B, C, D, E and F are for information only.
xii
ISO/IEC 1539 : 1991 (E)
Introduction
Standard programming language Fortran
This International Standard specifies the form and establ
...