This manual contains the complete description of the Compaq Fortran (formerly DIGITAL Fortran) programming language, which includes Fortran 95, Fortran 90, and High Performance Fortran language features. It contains information on language syntax and semantics, on adherence to various Fortran standards, and on extensions to those standards.

This manual applies to the following:

For details on the features of the compilers and how to improve the run-time performance of Fortran programs, see your user manual or programmer's guide.

For more information on the Compaq Fortran products, see

Intended Audience

This manual is intended for experienced applications programmers who have a basic understanding of Fortran concepts and the Fortran 95/90 language, and are using Compaq Fortran in either a single-platform or multiplatform environment.

Some familiarity with parallel programming concepts and your operating system is helpful. This manual is not a Fortran or programming tutorial.

Structure of this Document

This manual consists of the following chapters and appendixes:

Associated Documents

The following documents contain information directly related to the topics in this manual:

Other Sources of Information

This section alphabetically lists some commercially published documents that provide reference or tutorial information on Fortran 95, Fortran 90, and High Performance Fortran:

Compaq does not endorse these books or recommend them over other books on the same subjects.

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:

Language  Operating System  CPU1 
Compaq Fortran2   OpenVMS  Alpha 
  Tru64 UNIX3  Alpha 
  Linux  Alpha 
  Microsoft® Windows® 2000  ia32 
  Microsoft Windows NT® 4.0  ia32 
  Microsoft Windows 98  ia32 
  Microsoft Windows Me  ia32 
  Microsoft Windows 95  ia32 
  Microsoft 64-bit Windows  ia64 
1 See below for a description of ia32 and ia64.
2 Formerly the DIGITAL Fortran language.
3 Formerly the DIGITAL UNIX operating system.

Information in this manual applies to all supported platforms unless it is otherwise labeled for a specific platform, as follows:

VMS  Applies to OpenVMS on Alpha processors. 
U*X  Applies to Tru64 UNIX and Linux on Alpha processors. 
TU*X  Applies to Tru64 UNIX on Alpha processors. 
WNT  Applies to Microsoft Windows 2000 and Windows NT 4.0 on AMDTM and Intel® x86 processors, and 64-bit Windows operating systems on Intel IA-64 processors. 
W9*  Applies to Microsoft Windows 98, Windows Millennium Edition (Me), and Windows 95 on AMD and x86 processors. 
Alpha  Applies to operating systems on Alpha processors. 
ia32  Applies to 32-bit Windows operating systems on AMD and x86 processors. 
ia64  Applies to 64-bit Windows operating systems on IA-64 processors. 

For example, the ASM intrinsic function is labeled "(Alpha only)", so this intrinsic function is valid only for operating systems running on Alpha processors.

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:

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

Send Us Your Comments

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

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 Compaq's 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.

Conventions Used in this Manual

Table 1 describes the conventions used in this manual.

Table 1 Conventions Used in This Manual

Convention  Meaning 
{      }
Large braces enclose lists from which you must choose one item. For example:
{ STATUS    }
{ DISP      }
. . .
In code examples, a horizontal ellipsis means that not all of the statements are shown. In syntax forms, the symbol means that the item preceding the ellipsis can be repeated. For example:
s[,s] ...
[ ]  Square brackets enclose items that are optional in statements; for example:

In examples, square brackets are used to show arrays. 

A vertical ellipsis in a figure means that not all of the statements are shown. 
INTRINSIC, D_LINES   Uppercase letters indicate statement keywords and OpenVMS compiler options. 
monospaced   This typeface indicates a Tru64 UNIX command or pathname, and is also used in code examples. 
compiler option  This term refers to OpenVMS qualifiers, Tru64 UNIX and Linux options, and Windows options that can be used on the compiler command line. 
cat(1)   Cross-references to online reference pages include the appropriate section number in parentheses. For example, a reference to cat(1) indicates that you can find the material on the cat command in Section 1 of the reference pages. To read online reference pages, use the man command. Your operating system documentation also includes reference page descriptions. 
extensions   This color indicates extensions to the Fortran 95 Standard. These extensions may or may not be implemented by other compilers that conform to the language standard.
Fortran  This term refers to language information that is common to ANSI FORTRAN 77, ANSI/ISO Fortran 95/90, and Compaq Fortran. 
Fortran 95/90  This term refers to language information that is common to ANSI/ISO Fortran 95 and ANSI/ISO Fortran 90. 
Fortran 95  This term refers to language features of ANSI/ISO Fortran 95. 
Fortran 90  This term refers to language features of ANSI/ISO Fortran 90. 
Compaq Parallel Software Environment  This term refers to an optional license and software that allows parallel execution of programs. Without this option, programs can only execute on a single processor, either as a scalar (non-parallel) program or as a (special case) single processor parallel program.  
integer  This term refers to the INTEGER(KIND=1), INTEGER(KIND=2), INTEGER (INTEGER(KIND=4)), and INTEGER(KIND=8) data types as a group. 
real  This term refers to the REAL (REAL(KIND=4)), DOUBLE PRECISION (REAL(KIND=8)), and REAL(KIND=16) data types as a group. 
REAL  This term refers to the default data type of objects declared to be REAL. REAL is equivalent to REAL(KIND=4), unless a compiler option specifies otherwise. 
complex  This term refers to the COMPLEX (COMPLEX(KIND=4)), DOUBLE COMPLEX (COMPLEX(KIND=8)), and COMPLEX(KIND=16) data types as a group. 
logical  This term refers to the LOGICAL(KIND=1), LOGICAL(KIND=2), LOGICAL (LOGICAL(KIND=4)), and LOGICAL(KIND=8) data types as a group. 
Compaq Fortran, DIGITAL Fortran These terms refer to the same language. 
OpenVMS, VMS  These terms refer to the same operating system. 
Tru64 UNIX, DIGITAL UNIX   These terms refer to the same operating system. 
Windows systems  This term refers to all supported Microsoft® Windows® operating systems. (See Platform Labels.) 
(VMS only)  This style is used in platform labels and to emphasize text. 
<Tab> This symbol indicates a nonprinting tab character. 

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