E.1 Platform-Independent Extensions

This section summarizes the Compaq Fortran 77 extensions that are available on all platforms. The meaning of the extension may differ depending on which platform you are using.

Coding Rules

The following are platform-independent extensions to coding rules:

• Tab-formatting as a method to code lines (see Section 1.5.2)

• An exclamation point (!) as a comment indicator (see Section 1.5.3.1)

• The letter D as a debugging statement indicator in column 1 (see Section 1.5.3.2)

• An optional statement field width of 132 columns (see Section 1.5.5)

Symbolic Names

The following are platform-independent extensions to creating symbolic names (see Section 1.3.3):

• The dollar sign ($) and underscore (_) as valid name characters

• A limit of 31 characters in the symbolic name

Character Set

The following are platform-independent extensions to the FORTRAN-77 character set (see Section 1.4):

Compilation Control Statements

The following statements are platform-independent extensions that influence compilation (see Section 1.6):

• INCLUDE statement format:

     INCLUDE 'full-file-name[/[NO]LIST]'
  

• OPTIONS statement qualifiers:

     /NOASSUME
  
              { ALL           }
              { [NO]BOUNDS    }
     /CHECK = { [NO]OVERFLOW  }
              { [NO]UNDERFLOW }
              {               }
              { NONE          }
  
     /NOCHECK
  
                { BIG_ENDIAN    }
                { CRAY          }
                { FDX           }
                {               }
                { FGX           }
     /CONVERT = { IBM           }
                { LITTLE_ENDIAN }
                {               }
                { NATIVE        }
                { VAXD          }
                { VAXG          }
                {               }
  
     /[NO]EXTEND_SOURCE
     /[NO]F77
     /[NO]I4
     /[NO]RECURSIVE
  

  Data Types

  The following are platform-independent data type extensions (see Section 2.1):

  BYTE	INTEGER*1	REAL*8
  LOGICAL*1	INTEGER*2	COMPLEX*8
  LOGICAL*2	INTEGER*4	COMPLEX*16
  LOGICAL*4	REAL*4

  Data Items

  The following are platform-independent data item extensions:

  • Binary constants (see Section 2.2.1.4)

  • Octal and hexadecimal constants (see Section 2.2.1.4)

  • Hollerith constants (see Section 2.2.1.7)

  • Records and structures (see Section 2.2.5)

  Expressions

  Expressions are automatically converted to the necessary data type before combining with another operand. (See Section 2.3.1.2.)

  Logical Expressions

  The following are platform-independent logical expression extensions (see Section 2.3.4):

  • .XOR. as a synonym for .NEQV.

  • Integers as valid logical elements

  Assignment Statements

  On all platforms, you can specify the aggregate assignment statement extension (see Section 3.4).

  Specification Statements

  The following are platform-independent specification statement extensions:

  • AUTOMATIC and STATIC (see Section 4.1)

  • IMPLICIT NONE (see Section 4.9)

  • NAMELIST (see Section 4.11)

  • POINTER (see Section 4.13)

  • RECORD (see Section 4.15)

  • Structure declaration (see Section 4.17)

  • VOLATILE (see Section 4.18)

  Control Statements

  The following are platform-independent control statement extensions:

  • DO WHILE (see Section 5.4.2)

  • END DO (see Section 5.4)

  Built-In Functions

  The following are platform-independent built-in function extensions (see Section 6.1.2):

  • %VAL

  • %REF

  • %LOC

  I/O Statements

  The following are platform-independent I/O statement extensions::

  • A namelist specifier as a control list parameter (see Section 7.1.1.5)

  • An aggregate reference as an I/O list parameter (see Section 7.1.2)

  • List-directed internal READ statement (see Section 7.2.4.2)

  • List-directed internal WRITE statement (see Section 7.3.4.2)

  • REWRITE statement (see Section 7.4)

  • ACCEPT statement (see Section 7.5)

  • TYPE statement (see Section 7.6)

  I/O Formatting

  The following are platform-independent I/O formatting extensions:

  • The letter O as a field descriptor to transfer octal values (see Section 8.3.1.2)

  • The letter Z as a field descriptor to transfer hexadecimal values (see Section 8.3.1.3)

  • Variable format expressions (see Section 8.3.7)

  • The dollar sign ($) as an edit descriptor to modify carriage control (see Section 8.5.2)

  • The letter Q as an edit descriptor to return the number of characters to be transferred from an input file (see Section 8.5.3)

  • Default field descriptor values (see Table 8-4)

  • The dollar sign ($) as a carriage control character (see Table 8-5)

  • ASCII NUL as a carriage control character (see Table 8-5)

  Auxiliary I/O Statements

  The following are platform-independent auxiliary I/O statement extensions (see Chapter 9 for OpenVMS details or Chapter 10 for Tru64 UNIX details):

  • CLOSE statement keywords:

    • STATUS value: 'SAVE' as a synonym for 'KEEP'

    • DISPOSE (or DISP) value: 'SAVE' as a synonym for 'KEEP'

  • DELETE statement

  • INQUIRE statement specifiers:

    • CARRIAGECONTROL

    • CONVERT

    • FORM value: 'UNKNOWN'

    • FORMATTED value: 'NO'

    • ORGANIZATION values: 'SEQUENTIAL', 'RELATIVE', and 'UNKNOWN'

    • RECORDTYPE

    • SEQUENTIAL value: 'NO'

    • UNFORMATTED value: 'NO'

  • OPEN statement keywords:

    • ACCESS value: 'APPEND'

    • ASSOCIATEVARIABLE

    • BLOCKSIZE

    • BUFFERCOUNT

    • CARRIAGECONTROL

    • CONVERT

    • DEFAULTFILE

    • DISPOSE

    • NAME as a synonym for FILE

    • MAXREC

    • ORGANIZATION value: 'SEQUENTIAL' and 'RELATIVE'

    • READONLY

    • RECORDSIZE

    • RECORDTYPE

    • TYPE as a synonym for STATUS

    • USEROPEN

  • UNLOCK statement

  Compiler Directives

  The following are platform-independent general compiler directive extensions (see Section 11.2):

  • ALIAS

  • IDENT

  • PSECT

  • TITLE and SUBTITLE

  Additional Language Features

  The following are additional platform-independent language extensions that facilitate compatibility with other versions of Fortran:

  • DEFINE FILE statement (see Section A.1)

  • ENCODE and DECODE statements (see Section A.2)

  • FIND statement (see Section A.3)

  • NOF77 interpretation of the EXTERNAL statement (see Section A.4)

  • AND, OR, XOR, LSHIFT, RSHIFT intrinsics (see Section A.8)

  • An octal form for integer constants (see Section A.5)

    Be aware that on Alpha processors, you must specify the compiler option VMS to use this extension.

  • An alternative syntax for the PARAMETER statement (see Section A.6)

  • VIRTUAL statement (see Section A.7)

  • An alternative syntax for bit constants (see Section A.9)

  • An alternative syntax for a record specifier (see Section A.11)

  Intrinsic Procedures

  The following are platform-independent intrinsic function extensions (see Section C.2):

  ACOSD	CDLOG[1]	IBCLR	NOT
  ASIND	CDSIN[1]	IBITS	NWORKERS
  ATAND	CDSQRT[1]	IBSET	SIND
  ATAN2D	COSD	IEOR	SIZEOF
  BTEST	DCMPLX	IMAG	TAND
  CDABS[1]	DFLOAT	IOR	ZEXT
  CDCOS[1]	DREAL	ISHFT
  CDEXP[1]	IAND	ISHFTC
  [1] Double precision complex intrinsics can also begin with the letter Z (see Section C.2). For example, CDABS can also be spelled ZABS.

  System Subprograms

  The following are platform-independent system subprogram extensions (see Section D.1):

  DATE	MVBITS	TIME
  EXIT	RAN
  IDATE	SECNDS

  Symbolic Debugging Facility

  On all platforms, you can use a symbolic debugger to locate program run-time errors. For more information, see your user manual and the appropriate manual in your system documentation set.

  Procedure-Calling Conventions

  Compiled programs conform to the conventions used by your system (Tru64 UNIX, or OpenVMS) on your type of processor (Alpha or VAX). For more information, see your user manual.

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