CONTENTS

  Title Page

  Copyright Page

  Preface

  New Features

  1      Compiling DEC Fortran Programs

  1.1     Functions of the Compiler

  1.2     The FORTRAN Command
    1.2.1      Specifying Input Files
    1.2.2      Specifying Output Files
    1.2.3      Qualifiers to the FORTRAN Command
      1.2.3.1      /ANALYSIS_DATA Qualifier
      1.2.3.2      /ASSUME Qualifier
      1.2.3.3      /BLAS Qualifier
      1.2.3.4      /CHECK Qualifier
      1.2.3.5      /CONVERT Qualifier
      1.2.3.6      /CROSS_REFERENCE Qualifier
      1.2.3.7      /D_LINES Qualifier
      1.2.3.8      /DEBUG Qualifier
      1.2.3.9      /DESIGN Qualifier
      1.2.3.10     /DIAGNOSTICS Qualifier
      1.2.3.11     /DIRECTIVES Qualifier
      1.2.3.12     /DML Qualifier
      1.2.3.13     /ERROR_LIMIT Qualifier
      1.2.3.14     /EXTEND_SOURCE Qualifier
      1.2.3.15     /F77 Qualifier
      1.2.3.16     /G_FLOATING Qualifier
      1.2.3.17     /I4 Qualifier
      1.2.3.18     /LIBRARY Qualifier
      1.2.3.19     /LIST Qualifier
      1.2.3.20     /MACHINE_CODE Qualifier
      1.2.3.21     /MATH_LIBRARY Qualifier
      1.2.3.22     /OBJECT Qualifier
      1.2.3.23     /OPTIMIZE Qualifier
      1.2.3.24     /PARALLEL Qualifier
      1.2.3.25     /RECURSIVE Qualifier
      1.2.3.26     /SHOW Qualifier
      1.2.3.27     /STANDARD Qualifier
      1.2.3.28     /SYNCHRONOUS_EXCEPTIONS Qualifier
      1.2.3.29     /TERMINAL Qualifier
      1.2.3.30     /VECTOR Qualifier
      1.2.3.31     /WARNINGS Qualifier

  1.3     Using Text Libraries
    1.3.1      Using the LIBRARY Commands
    1.3.2      Naming Text Modules
    1.3.3      Specifying Library Files on the FORTRAN Command Line
    1.3.4      Search Order of Libraries
      1.3.4.1      User-Supplied Default Libraries
      1.3.4.2      System-Supplied Default Library

  1.4     Using CDD/Repository
    1.4.1      Accessing CDD/Repository from DEC Fortran Programs
    1.4.2      DEC Fortran and CDD/Repository Data Types

  1.5     Compiler Limits, Diagnostic Messages, and Error Conditions
    1.5.1      Compiler Limits
    1.5.2      Compiler Diagnostic Messages and Error Conditions

  1.6     Compiler Output Listing Format
    1.6.1      Source Code Section
    1.6.2      Machine Code Section
    1.6.3      Storage Map Section
    1.6.4      Compilation Summary Section

  2      Linking and Running DEC Fortran Programs

  2.1     Linking DEC Fortran Programs
    2.1.1      Functions of the Linker
    2.1.2      The LINK Command
      2.1.2.1      Linker Output File Qualifiers
      2.1.2.2      /DEBUG and /TRACEBACK Qualifiers
      2.1.2.3      Linker Input File Qualifiers
      2.1.2.4      Linker Symbol Table Qualifier
      2.1.2.5      Linker Options File Qualifier
      2.1.2.6      Other Linker Qualifiers
    2.1.3      Linker Messages

  2.2     Running DEC Fortran Programs
    2.2.1      The RUN Command
    2.2.2      System Processing at Image Exit
    2.2.3      Interrupting a Program
    2.2.4      Returning Status Values to the Command Interpreter

  2.3     Finding and Correcting Run-Time Errors

  3      Using the VMS Debugger

  3.1     Overview

  3.2     Getting Started with the Debugger
    3.2.1      Compiling and Linking a Program to Prepare for Debugging
    3.2.2      Establishing the Debugging Configuration
    3.2.3      Invoking the Debugger
    3.2.4      Ending a Debugging Session
    3.2.5      Notes on Debugger Support for DEC Fortran

  3.3     Sample Debugging Session

  3.4     Debugger Command Summary
    3.4.1      Starting and Terminating a Debugging Session
    3.4.2      Controlling and Monitoring Program Execution
    3.4.3      Examining and Manipulating Data
    3.4.4      Controlling Type Selection and Symbolization
    3.4.5      Controlling Symbol Lookup
    3.4.6      Displaying Source Code
    3.4.7      Using Screen Mode
    3.4.8      Editing Source Code
    3.4.9      Defining Symbols
    3.4.10     Using Keypad Mode
    3.4.11     Using Command Procedures and Log Files
    3.4.12     Using Control Structures
    3.4.13     Debugging Multiprocess Programs
    3.4.14     Additional Commands

  3.5     Debugging Multiprocess Programs

  4      DEC Fortran Input/Output

  4.1     Overview of DEC Fortran I/O
    4.1.1      Identifying Logical Input/Output Units
    4.1.2      Interprocess Communication
    4.1.3      Types of I/O Statements
    4.1.4      Forms of I/O Statements

  4.2     Elements of I/O Processing
    4.2.1      File Specifications
    4.2.2      Logical Names and Logical Unit Numbers
      4.2.2.1      FORTRAN Logical Names
      4.2.2.2      Implied FORTRAN Logical Unit Numbers
      4.2.2.3      File Specification in an OPEN Statement
      4.2.2.4      Assigning Files to Logical Units
    4.2.3      File Organizations, I/O Record Types, and Access Modes
      4.2.3.1      File Organizations
      4.2.3.2      Scratch Files
      4.2.3.3      Internal Files
      4.2.3.4      I/O Record Formats
      4.2.3.5      Record Access Modes

  4.3     Buffering of Output Data

  5      Error Processing

  5.1     Run-Time Library Default Error Processing

  5.2     Using the ERR and END Specifiers

  5.3     Using the IOSTAT Specifier

  6      Using DEC Fortran in the Common Language Environment

  6.1     VMS Procedure-Calling Standard
    6.1.1      Register and Stack Usage
    6.1.2      Return Values of Procedures
    6.1.3      Argument Lists

  6.2     Argument-Passing Mechanisms
    6.2.1      Passing Arguments by Reference-%REF Function
    6.2.2      Passing Arguments by Descriptor-%DESCR Function
    6.2.3      Passing Arguments by Immediate Value-%VAL Function
    6.2.4      Passing Addresses-%LOC Function
    6.2.5      Examples of Argument Passing Built-In Functions
    6.2.6      Object Code Examples
      6.2.6.1      Argument-Passing Examples
      6.2.6.2      Examples of Argument List Built-In Functions
      6.2.6.3      Character Function Example

  6.3     VMS System Routines
    6.3.1      VMS Run-Time Library Routines
    6.3.2      VMS System Services Routines

  6.4     Calling Routines-General Considerations

  6.5     Calling VMS System Services
    6.5.1      Obtaining Values for System Symbols
    6.5.2      Calling System Services by Function Reference
    6.5.3      Calling System Services as Subroutines
    6.5.4      Passing Arguments to System Services
      6.5.4.1      Immediate Value Arguments
      6.5.4.2      Address Arguments
      6.5.4.3      Descriptor Arguments
      6.5.4.4      Data Structure Arguments
      6.5.4.5      Examples of Passing Arguments

  7      Using VMS Record Management Services

  7.1     RMS Data Structures
    7.1.1      Using FORSYSDEF Modules to Manipulate RMS Data Structures
    7.1.2      The File Access Block
    7.1.3      The Record Access Block
    7.1.4      The Name Block
    7.1.5      Extended Attributes Blocks

  7.2     RMS Services
    7.2.1      Declaring RMS System Service Names
    7.2.2      Arguments to RMS Services
    7.2.3      Checking Status from RMS Services
    7.2.4      Opening a File
    7.2.5      Closing a File
    7.2.6      Writing Data
    7.2.7      Reading Data
    7.2.8      Other Services

  7.3     User-Written Open Procedures
    7.3.1      Examples of USEROPEN Routines
    7.3.2      RMS Control Structures

  7.4     Example of Block Mode I/O

  8      Interprocess Communications

  8.1     Local Processes-Sharing and Exchanging Data
    8.1.1      Sharing Images in Shareable Image Libraries
    8.1.2      Sharing Data in Installed Common Areas
    8.1.3      Synchronizing Access
    8.1.4      Sharing Data in Files
    8.1.5      Using Mailboxes to Pass Information
    8.1.6      Sending and Receiving Data Using Mailboxes

  8.2     Remote Processes-Sharing and Exchanging Data
    8.2.1      Remote File Access
    8.2.2      Network Task-to-Task Communication

  9      Condition-Handling Facilities

  9.1     Default Condition Handler

  9.2     User-Program Interactions with the CHF
    9.2.1      Establishing and Removing Condition Handlers
    9.2.2      Signaling a Condition
    9.2.3      Condition Values and Symbols Passed to CHF

  9.3     Operations Performed in Condition Handlers

  9.4     Coding Requirements of Condition Handlers

  9.5     Returning from a Condition Handler

  9.6     Use of LIB$ Routines as Condition Handlers
    9.6.1      Overflow/Underflow Detection Enabling Routines
    9.6.2      Floating Underflow Exceptions
      9.6.2.1      Specifying CHECK=UNDERFLOW
      9.6.2.2      Establishing a Handler for Underflow
      9.6.2.3      Enabling and Disabling Underflow Exceptions
    9.6.3      Floating Reserved Operand Faults
    9.6.4      Matching Condition Values to Determine Program Behavior
    9.6.5      Converting Faults and Traps
    9.6.6      Changing a Signal to a Return Status
    9.6.7      Changing a Signal to a Stop

  9.7     Condition Handler Examples

  10     DEC Fortran Implementation Notes

  10.1    DEC Fortran Program Section Usage

  10.2    Storage Allocation and Fixed-Point Data Types
    10.2.1     Integer Data Types
      10.2.1.1     Relationship of INTEGER * 2 and INTEGER * 4 Values
      10.2.1.2     Integer Constant Typing
      10.2.1.3     Integer-Valued Intrinsic Functions
    10.2.2     BYTE (LOGICAL * 1) Data Type
    10.2.3     Zero-Extend Intrinsic Functions for Converting Data Types

  10.3    Iteration Count Model for Indexed DO Loops
    10.3.1     Cautions Concerning Program Transportability
    10.3.2     Iteration Count Computation

  10.4    ENTRY Statement Arguments

  10.5    Floating-Point Data
    10.5.1     Floating-Point Data Characteristics
      10.5.1.1     Reserved Operand Faults
      10.5.1.2     Representation of 0.0
      10.5.1.3     Sign Bit Tests
    10.5.2     Effect of the /G_FLOATING Qualifier
    10.5.3     Conversion Between D_floating and G_floating Data Types
      10.5.3.1     Run-Time Library Conversion Functions
      10.5.3.2     Run-Time Library Conversion Subroutines
      10.5.3.3     Sample Conversions

  11     Using Structures and Records

  11.1    Structures

  11.2    Records

  12     Using Character Data

  12.1    Character Substrings

  12.2    Building Character Strings

  12.3    Character Constants

  12.4    Declaring Character Data

  12.5    Initializing Character Variables

  12.6    Passed-Length Character Arguments

  12.7    Character Intrinsic Functions
    12.7.1     CHAR Intrinsic Function
    12.7.2     ICHAR Intrinsic Function
    12.7.3     INDEX Intrinsic Function
    12.7.4     LEN Intrinsic Function
    12.7.5     LGE, LGT, LLE, LLT Intrinsic Functions

  12.8    Character I/O

  12.9    Character Data Examples

  13     Using Indexed Files

  13.1    Creating an Indexed File

  13.2    Writing Indexed Files
    13.2.1     Duplicate Values in Key Fields
    13.2.2     Preventing the Indexing of Alternate Key Fields

  13.3    Reading Indexed Files

  13.4    Updating Records

  13.5    Deleting Records

  13.6    Current Record and Next Record Pointers

  13.7    Exception Conditions

  A   Contents of the FORTRAN System Library FORSYSDEF

  B   Data Storage and Representation

  B.1     Summary of Data Types and Characteristics

  B.2     Integer Data Representations
    B.2.1      INTEGER * 1 Representation
    B.2.2      INTEGER * 2 Representation
    B.2.3      INTEGER * 4 Representation

  B.3     Logical Data Representations
    B.3.1      LOGICAL * 1 (BYTE) Representation
    B.3.2      LOGICAL * 2 and LOGICAL * 4 Representation

  B.4     Floating-Point Representations
    B.4.1      REAL * 4 (F_floating)
    B.4.2      REAL * 8 (D_floating)
    B.4.3      REAL * 8 (G_floating)
    B.4.4      REAL * 16 (H_floating)
    B.4.5      COMPLEX * 8 (F_floating)
    B.4.6      COMPLEX * 16 (D_floating)
    B.4.7      COMPLEX * 16 (G_floating)

  B.5     Character Representation

  B.6     Hollerith Representation

  C   Converting Unformatted Files

  C.1     Supported Unformatted Numeric File Formats

  C.2     Methods of Specifying the Data Format
    C.2.1      OPEN statement CONVERT='keyword' Method
    C.2.2      Logical Name FOR$CONVERT nnn Method
    C.2.3      OPTIONS Statement /CONVERT= keyword Method
    C.2.4      FORTRAN Command /CONVERT= keyword Qualifier Method
    C.2.5      Additional Notes on Unformatted Data Files

  D   Using System Services-Examples

  D.1     Calling RMS Procedures

  D.2     Using an AST Routine

  D.3     Accessing Devices Using Synchronous I/O

  D.4     Communicating with Other Processes

  D.5     Sharing Data

  D.6     Displaying Data at Terminals

  D.7     Creating, Accessing, and Ordering Files

  D.8     Accessing Help Libraries

  D.9     Creating and Managing Other Processes

  E   Compatibility With FORTRAN-66

  E.1     Minimum Iteration Count for DO Loops

  E.2     EXTERNAL Statement

  E.3     OPEN Statement Keyword Defaults
    E.3.1      BLANK Keyword Default
    E.3.2      OPEN Statement's STATUS Keyword Default

  E.4     X Format Edit Descriptor

  E.5     Open Operation on a Connected Unit

  F   Compatibility With PDP-11 FORTRAN

  F.1     Language Differences
    F.1.1      Logical Tests
    F.1.2      Floating-Point Results
    F.1.3      Character and Hollerith Constants
    F.1.4      Logical Unit Numbers
    F.1.5      Assigned GO TO Label List
    F.1.6      DISPOSE= ' PRINT ' Specification

  F.2     Run-Time Support Differences
    F.2.1      Run-Time Library Error Numbers
    F.2.2      Error Handling and Reporting
      F.2.2.1      Continuing After Errors
      F.2.2.2      I/O Errors with IOSTAT or ERR Specified
      F.2.2.3      OPEN/CLOSE Statement Errors
    F.2.3      OPEN Statement Keywords

  F.3     Utility Subprograms
    F.3.1      ASSIGN Subprogram
    F.3.2      CLOSE Subprogram
    F.3.3      ERRSET Subprogram
    F.3.4      ERRSNS Subprogram
    F.3.5      ERRTST Subprogram
    F.3.6      FDBSET Subprogram
    F.3.7      IRAD50 Subprogram
    F.3.8      RAD50 Function
    F.3.9      RAN Function
    F.3.10     RANDU Subprogram
    F.3.11     R50ASC Subprogram
    F.3.12     USEREX Subprogram

  G   Diagnostic Messages

  G.1     Diagnostic Messages from the DEC Fortran Compiler
    G.1.1      Source Program Diagnostic Messages
    G.1.2      Compiler-Fatal Diagnostic Messages

  G.2     Diagnostic Messages from the Run-Time System

  G.3     DICTIONARY Error Messages

  EXAMPLES

  1-1        Sample Listing of Source Code

  1-2        Sample Listing of Machine Code

  1-3        Sample Storage Map Section

  1-4        Sample Compilation Summary

  2-1        Sample DEC Fortran Program and Traceback

  3-1        Sample Program SQUARES

  3-2        Sample Debugging Session Using Program SQUARES

  3-3        Sample DEC Fortran Multiprocessing Source Program

  3-4        Sample Multiprocessing Debugging Session

  6-1        Subroutine Using a Data Structure Argument

  6-2        Ctrl/C Trapping Example

  12-1       Character Data Program Example (Source)

  12-2       Character Data Program Example (Output)

  G-1        Sample Diagnostic Messages (Listing Format)

  FIGURES

  1-1        Creating and Using a Text Library

  6-1        Structure of a VMS VAX Argument List

  6-2        Example of a VMS VAX Argument List

  9-1        Sample Stack Scan for Condition Handlers

  9-2        Effects of Calls to LIB$SIGNAL or LIB$STOP

  10-1       General Format of Floating-Point Data

  TABLES

  1 Conventions Used in This Document

  1-1        FORTRAN Command Qualifiers

  1-2        Commands to Control Library Files

  1-3        Compiler Limits

  2-1        LINK Command Qualifiers

  2-2        /DEBUG and /TRACEBACK Qualifiers

  4-1        Available I/O Statements

  4-2        Predefined System Logical Names

  4-3        Implicit FORTRAN Logical Units

  4-4        Valid Combinations of Record Access Mode and File Organization

  5-1        Summary of Run-Time Errors

  6-1        VMS VAX Register Usage

  6-2        Function Return Values

  6-3        Run-Time Library Facilities

  6-4        System Services

  6-5        DEC Fortran Implementation of VMS Data Types

  6-6        Variable Data Type Requirements

  7-1        RMS Fields Available with USEROPEN

  9-1        Severity Codes for Exception Condition Values

  9-2        Condition-Handler Function Return Values

  10-1       PSECT Names and Attributes

  10-2       DEC Fortran PSECT Attributes

  A-1        Contents of System Library FORSYSDEF

  B-1        DEC Fortran Data Types and Storage

  C-1        Nonnative Numeric Formats, Keywords, and Supported Data Types

  F-1        Default Logical Unit Numbers

  G-1        Source Program Diagnostic Messages

  G-2        Run-Time Diagnostic Messages

  G-3        Run-Time Diagnostic Messages for Parallel Processing

  G-4        CRX Error Messages