Programmer's Guide Conventions

This section discusses the following:

General Conventions

The Programmer's Guide uses the following general conventions. (Note that in most cases, blanks are not significant in Fortran 90 or 95.)

When You See This Here Is What It Means
Extensions to Fortran 95 Dark teal type indicates extensions to the Fortran 95 Standard. These extensions may or may not be implemented by other compilers that conform to the language standard.
DF, LINK, FL32 Uppercase (capital) letters indicate filenames and MS®-DOS®-level commands used in the command console.
expression Words in italics indicate placeholders for information that you must supply. A file-name is an example of this kind of information. Italics are also used to introduce new terms.
[optional item] Items inside single square brackets are optional. In some examples, square brackets are used to show arrays.
{choice1 | choice2} Braces and a vertical bar indicate a choice among two or more items. You must choose one of the items unless all of the items are also enclosed in square brackets. 

s[, s]...
A horizontal ellipsis (three dots) following an item indicates that the item preceding the ellipsis can be repeated. In code examples, a horizontal ellipsis means that not all of the statements are shown.
compiler option This term refers to Windows options, OpenVMS qualifiers, and Tru64 UNIX and Linux options that can be used on the compiler command line. 
!  Comment line
WRITE (*,*) 'Hello &
&World'
This kind of type is used for program examples, program output, and error messages within the text. An exclamation point marks the beginning of a comment in sample programs. Continuation lines are indicated by an ampersand ( & ) after the code at the end of a line to be continued and before the code on the following line.
AUTOMATIC, INTRINSIC, WRITE Bold capital letters indicate Compaq® Fortran statements, functions, subroutines, and keywords. Keywords are a required part of statement syntax, unless enclosed in brackets as explained above.
In the sentence, "The following steps occur when a DO WHILE statement is executed," the phrase DO WHILE is a Compaq Fortran keyword.
Bold lowercase letters are used for keywords of other languages. In the sentence, "A Fortran subroutine is the equivalent of a function of type void in C," the word void is a keyword of C.
Fortran This term refers to language information that is common to ANSI FORTRAN 77, ANSI/ISO Fortran 95 and 90, and Compaq Fortran (formerly DIGITAL 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 information that is common to ANSI/ISO Fortran 95.
Fortran 90 This term refers to language information that is common to ANSI/ISO Fortran 90.
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 labels WNT and W9* in Platform Labels below.) 
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)) and DOUBLE PRECISION (REAL(KIND=8)) data types as a group.
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.

Syntax Conventions

The Programmer's Guide uses certain conventions for language syntax. For example, consider the following syntax for the PARAMETER statement:

PARAMETER [(] c = expr [, c = expr ]...[)]

This syntax shows that to use this statement, you must specify the following:

The dark teal brackets ([   ]) indicate that the optional parentheses are an extension to standard Fortran.

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). For example, Microsoft® Windows® 98 on x86 is a platform.

Information applies to all supported platforms unless it is otherwise labeled for a specific platform (or platforms), as follows:

VMS  Applies to OpenVMSTM 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 2000 and Windows NT® 4.0 operating systems on AMD 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 operating systems on AMD and Intel x86 processors.
Alpha  Applies to operating systems on Alpha processors.
ia32  Applies to 32-bit Windows operating systems on AMD and Intel x86 processors (see "System Requirements and Optional Software" in Compaq Visual Fortran Installing and Getting Started).
ia64  Applies to 64-bit Windows operating systems on IA-64 processors.