Fortran 90 Programmer’s Reference First Edition Product Number: B3909DB Fortran 90 Compiler for HP-UX Document Number: B3908-90002 October 1998 Edition: First Document Number: B3908-90002 Remarks: Released October 1998. Initial release. Notice Copyright Hewlett-Packard Company 1998. All Rights Reserved. Reproduction, adaptation, or translation without prior written permission is prohibited, except as allowed under the copyright laws. The information contained in this document is subject to change without notice. Hewlett-Packard makes no warranty of any kind with regard to this material, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. Hewlett-Packard shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing, performance or use of this material. Contents Preface . xix New in HP Fortran 90 V2.0. .xx Scope. xxi Notational conventions . xxii Command syntax . xxiii Associated documents . xxiv 1 Introduction to HP Fortran 90 . 1 HP Fortran 90 features . .2 Source format . .2 Data types . .2 Pointers . .3 Arrays . .3 Control constructs . .3 Operators . .4 Procedures. .4 Modules . .5 I/O features . .5 Intrinsics . .6 2 Language elements . 7 Character set . .8 Lexical tokens . .9 Names. .9 Program structure . .10 Statement labels . .10 Statements . .11 Source format of program file . .13 Free source form . .13 Source lines . .14 Statement labels . .14 Spaces . .14 Comments . .15 Statement continuation . .15 Fixed source form . .16 Spaces . .16 Source lines . .16 Table of Contents i INCLUDE line . 19 3 Data types and data objects . 21 Intrinsic data types . 22 Type declaration for intrinsic types . 24 Implicit typing. 28 Constants. 29 Integer constants . 29 BOZ constants . 30 Hollerith constants . 30 Typeless constants . 31 Real constants . 33 Complex constants. 34 Character constants. 34 Logical constants . 35 Character substrings . 36 Character strings as automatic data objects . 37 Derived types . 39 Defining a derived type. 40 Sequence derived type . 41 Structure component. 41 Declaring a derived type-object . 43 Structure constructor . 43 Alignment of derived-type objects . 44 A derived-type example . 45 Pointers . 47 Pointer association status. 48 A pointer example . 49 4 Arrays . 51 Array fundamentals . 52 Array declarations . 54 Explicit-shape arrays . 55 Assumed-shape arrays . 56 Deferred-shape arrays . 58 Array pointers . 59 Allocatable arrays . 59 Assumed-size arrays . 61 Array sections. 63 Subscript triplet . 64 Vector subscripts . 65 Array-valued structure component references . 68 Array constructors . 71 ii Table of Contents Array expressions . ..