Using and Porting GNU Fortran

This manual documents how to run, install and port the GNU Fortran compiler, as well as its new features and incompatibilities, and how to report bugs. It corresponds to GNU Fortran version 0.5.23.

• GNU GENERAL PUBLIC LICENSE
  • Preamble
  • TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
  • How to Apply These Terms to Your New Programs
• Contributors to GNU Fortran
• Funding Free Software
• Funding GNU Fortran
• Protect Your Freedom--Fight "Look And Feel"
• Getting Started
• What is GNU Fortran?
• Compile Fortran, C, or Other Programs
• GNU Fortran Command Options
  • Option Summary
  • Options Controlling the Kind of Output
  • Shorthand Options
  • Options Controlling Fortran Dialect
  • Options to Request or Suppress Warnings
  • Options for Debugging Your Program or GNU Fortran
  • Options That Control Optimization
  • Options Controlling the Preprocessor
  • Options for Directory Search
  • Options for Code Generation Conventions
  • Environment Variables Affecting GNU Fortran
• News About GNU Fortran
• User-visible Changes
• The GNU Fortran Language
  • Direction of Language Development
  • ANSI FORTRAN 77 Standard Support
    • No Passing External Assumed-length
    • No Passing Dummy Assumed-length
    • No Pathological Implied-DO
    • No Useless Implied-DO
  • Conformance
  • Notation Used in This Chapter
  • Fortran Terms and Concepts
    • Syntactic Items
    • Statements, Comments, and Lines
    • Scope of Symbolic Names and Statement Labels
  • Characters, Lines, and Execution Sequence
    • GNU Fortran Character Set
    • Lines
    • Continuation Line
    • Statements
    • Statement Labels
    • Order of Statements and Lines
    • Including Source Text
  • Data Types and Constants
    • Data Types
      • Double Notation
      • Star Notation
      • Kind Notation
    • Constants
    • Integer Type
    • Character Type
  • Expressions
    • The %LOC() Construct
  • Specification Statements
    • NAMELIST Statement
    • DOUBLE COMPLEX Statement
  • Control Statements
    • DO WHILE
    • END DO
    • Construct Names
    • The CYCLE and EXIT Statements
  • Functions and Subroutines
    • The %VAL() Construct
    • The %REF() Construct
    • The %DESCR() Construct
    • Generics and Specifics
    • REAL() and AIMAG() of Complex
    • CMPLX() of DOUBLE PRECISION
    • MIL-STD 1753 Support
    • f77/f2c Intrinsics
    • Table of Intrinsic Functions
      • Abort Intrinsic
      • Abs Intrinsic
      • Access Intrinsic
      • AChar Intrinsic
      • ACos Intrinsic
      • AdjustL Intrinsic
      • AdjustR Intrinsic
      • AImag Intrinsic
      • AInt Intrinsic
      • Alarm Intrinsic
      • All Intrinsic
      • Allocated Intrinsic
      • ALog Intrinsic
      • ALog10 Intrinsic
      • AMax0 Intrinsic
      • AMax1 Intrinsic
      • AMin0 Intrinsic
      • AMin1 Intrinsic
      • AMod Intrinsic
      • And Intrinsic
      • ANInt Intrinsic
      • Any Intrinsic
      • ASin Intrinsic
      • Associated Intrinsic
      • ATan Intrinsic
      • ATan2 Intrinsic
      • BesJ0 Intrinsic
      • BesJ1 Intrinsic
      • BesJN Intrinsic
      • BesY0 Intrinsic
      • BesY1 Intrinsic
      • BesYN Intrinsic
      • Bit_Size Intrinsic
      • BTest Intrinsic
      • CAbs Intrinsic
      • CCos Intrinsic
      • Ceiling Intrinsic
      • CExp Intrinsic
      • Char Intrinsic
      • ChDir Intrinsic (subroutine)
      • ChMod Intrinsic (subroutine)
      • CLog Intrinsic
      • Cmplx Intrinsic
      • Complex Intrinsic
      • Conjg Intrinsic
      • Cos Intrinsic
      • CosH Intrinsic
      • Count Intrinsic
      • CPU_Time Intrinsic
      • CShift Intrinsic
      • CSin Intrinsic
      • CSqRt Intrinsic
      • CTime Intrinsic (subroutine)
      • CTime Intrinsic (function)
      • DAbs Intrinsic
      • DACos Intrinsic
      • DASin Intrinsic
      • DATan Intrinsic
      • DATan2 Intrinsic
      • Date_and_Time Intrinsic
      • DbesJ0 Intrinsic
      • DbesJ1 Intrinsic
      • DbesJN Intrinsic
      • DbesY0 Intrinsic
      • DbesY1 Intrinsic
      • DbesYN Intrinsic
      • Dble Intrinsic
      • DCos Intrinsic
      • DCosH Intrinsic
      • DDiM Intrinsic
      • DErF Intrinsic
      • DErFC Intrinsic
      • DExp Intrinsic
      • Digits Intrinsic
      • DiM Intrinsic
      • DInt Intrinsic
      • DLog Intrinsic
      • DLog10 Intrinsic
      • DMax1 Intrinsic
      • DMin1 Intrinsic
      • DMod Intrinsic
      • DNInt Intrinsic
      • Dot_Product Intrinsic
      • DProd Intrinsic
      • DSign Intrinsic
      • DSin Intrinsic
      • DSinH Intrinsic
      • DSqRt Intrinsic
      • DTan Intrinsic
      • DTanH Intrinsic
      • Dtime Intrinsic (subroutine)
      • EOShift Intrinsic
      • Epsilon Intrinsic
      • ErF Intrinsic
      • ErFC Intrinsic
      • ETime Intrinsic (subroutine)
      • ETime Intrinsic (function)
      • Exit Intrinsic
      • Exp Intrinsic
      • Exponent Intrinsic
      • Fdate Intrinsic (subroutine)
      • Fdate Intrinsic (function)
      • FGet Intrinsic (subroutine)
      • FGetC Intrinsic (subroutine)
      • Float Intrinsic
      • Floor Intrinsic
      • Flush Intrinsic
      • FNum Intrinsic
      • FPut Intrinsic (subroutine)
      • FPutC Intrinsic (subroutine)
      • Fraction Intrinsic
      • FSeek Intrinsic
      • FStat Intrinsic (subroutine)
      • FStat Intrinsic (function)
      • FTell Intrinsic (subroutine)
      • FTell Intrinsic (function)
      • GError Intrinsic
      • GetArg Intrinsic
      • GetCWD Intrinsic (subroutine)
      • GetCWD Intrinsic (function)
      • GetEnv Intrinsic
      • GetGId Intrinsic
      • GetLog Intrinsic
      • GetPId Intrinsic
      • GetUId Intrinsic
      • GMTime Intrinsic
      • HostNm Intrinsic (subroutine)
      • HostNm Intrinsic (function)
      • Huge Intrinsic
      • IAbs Intrinsic
      • IAChar Intrinsic
      • IAnd Intrinsic
      • IArgC Intrinsic
      • IBClr Intrinsic
      • IBits Intrinsic
      • IBSet Intrinsic
      • IChar Intrinsic
      • IDate Intrinsic (UNIX)
      • IDiM Intrinsic
      • IDInt Intrinsic
      • IDNInt Intrinsic
      • IEOr Intrinsic
      • IErrNo Intrinsic
      • IFix Intrinsic
      • Imag Intrinsic
      • ImagPart Intrinsic
      • Index Intrinsic
      • Int Intrinsic
      • Int2 Intrinsic
      • Int8 Intrinsic
      • IOr Intrinsic
      • IRand Intrinsic
      • IsaTty Intrinsic
      • IShft Intrinsic
      • IShftC Intrinsic
      • ISign Intrinsic
      • ITime Intrinsic
      • Kill Intrinsic (subroutine)
      • Kind Intrinsic
      • LBound Intrinsic
      • Len Intrinsic
      • Len_Trim Intrinsic
      • LGe Intrinsic
      • LGt Intrinsic
      • Link Intrinsic (subroutine)
      • LLe Intrinsic
      • LLt Intrinsic
      • LnBlnk Intrinsic
      • Loc Intrinsic
      • Log Intrinsic
      • Log10 Intrinsic
      • Logical Intrinsic
      • Long Intrinsic
      • LShift Intrinsic
      • LStat Intrinsic (subroutine)
      • LStat Intrinsic (function)
      • LTime Intrinsic
      • MatMul Intrinsic
      • Max Intrinsic
      • Max0 Intrinsic
      • Max1 Intrinsic
      • MaxExponent Intrinsic
      • MaxLoc Intrinsic
      • MaxVal Intrinsic
      • MClock Intrinsic
      • MClock8 Intrinsic
      • Merge Intrinsic
      • Min Intrinsic
      • Min0 Intrinsic
      • Min1 Intrinsic
      • MinExponent Intrinsic
      • MinLoc Intrinsic
      • MinVal Intrinsic
      • Mod Intrinsic
      • Modulo Intrinsic
      • MvBits Intrinsic
      • Nearest Intrinsic
      • NInt Intrinsic
      • Not Intrinsic
      • Or Intrinsic
      • Pack Intrinsic
      • PError Intrinsic
      • Precision Intrinsic
      • Present Intrinsic
      • Product Intrinsic
      • Radix Intrinsic
      • Rand Intrinsic
      • Random_Number Intrinsic
      • Random_Seed Intrinsic
      • Range Intrinsic
      • Real Intrinsic
      • RealPart Intrinsic
      • Rename Intrinsic (subroutine)
      • Repeat Intrinsic
      • Reshape Intrinsic
      • RRSpacing Intrinsic
      • RShift Intrinsic
      • Scale Intrinsic
      • Scan Intrinsic
      • Second Intrinsic (function)
      • Second Intrinsic (subroutine)
      • Selected_Int_Kind Intrinsic
      • Selected_Real_Kind Intrinsic
      • Set_Exponent Intrinsic
      • Shape Intrinsic
      • Short Intrinsic
      • Sign Intrinsic
      • Signal Intrinsic (subroutine)
      • Sin Intrinsic
      • SinH Intrinsic
      • Sleep Intrinsic
      • Sngl Intrinsic
      • Spacing Intrinsic
      • Spread Intrinsic
      • SqRt Intrinsic
      • SRand Intrinsic
      • Stat Intrinsic (subroutine)
      • Stat Intrinsic (function)
      • Sum Intrinsic
      • SymLnk Intrinsic (subroutine)
      • System Intrinsic (subroutine)
      • System_Clock Intrinsic
      • Tan Intrinsic
      • TanH Intrinsic
      • Time Intrinsic (UNIX)
      • Time8 Intrinsic
      • Tiny Intrinsic
      • Transfer Intrinsic
      • Transpose Intrinsic
      • Trim Intrinsic
      • TtyNam Intrinsic (subroutine)
      • TtyNam Intrinsic (function)
      • UBound Intrinsic
      • UMask Intrinsic (subroutine)
      • Unlink Intrinsic (subroutine)
      • Unpack Intrinsic
      • Verify Intrinsic
      • XOr Intrinsic
      • ZAbs Intrinsic
      • ZCos Intrinsic
      • ZExp Intrinsic
      • ZLog Intrinsic
      • ZSin Intrinsic
      • ZSqRt Intrinsic
  • Scope and Classes of Symbolic Names
    • Underscores in Symbol Names
• Other Dialects
  • Source Form
    • Carriage Returns
    • Tabs
    • Short Lines
    • Long Lines
    • Ampersand Continuation Line
  • Trailing Comment
  • Debug Line
  • Dollar Signs in Symbol Names
  • Case Sensitivity
  • VXT Fortran
    • Meaning of Double Quote
    • Meaning of Exclamation Point in Column 6
  • Fortran 90
  • Pedantic Compilation
  • Distensions
    • Implicit Argument Conversion
    • Ugly Assumed-Size Arrays
    • Ugly Complex Part Extraction
    • Ugly Null Arguments
    • Ugly Conversion of Initializers
    • Ugly Integer Conversions
    • Ugly Assigned Labels
• The GNU Fortran Compiler
  • Compiler Limits
  • Compiler Types
  • Compiler Constants
  • Compiler Intrinsics
    • Intrinsic Groups
    • Other Intrinsics
      • ACosD Intrinsic
      • AIMax0 Intrinsic
      • AIMin0 Intrinsic
      • AJMax0 Intrinsic
      • AJMin0 Intrinsic
      • ASinD Intrinsic
      • ATan2D Intrinsic
      • ATanD Intrinsic
      • BITest Intrinsic
      • BJTest Intrinsic
      • CDAbs Intrinsic
      • CDCos Intrinsic
      • CDExp Intrinsic
      • CDLog Intrinsic
      • CDSin Intrinsic
      • CDSqRt Intrinsic
      • ChDir Intrinsic (function)
      • ChMod Intrinsic (function)
      • CosD Intrinsic
      • DACosD Intrinsic
      • DASinD Intrinsic
      • DATan2D Intrinsic
      • DATanD Intrinsic
      • Date Intrinsic
      • DbleQ Intrinsic
      • DCmplx Intrinsic
      • DConjg Intrinsic
      • DCosD Intrinsic
      • DFloat Intrinsic
      • DFlotI Intrinsic
      • DFlotJ Intrinsic
      • DImag Intrinsic
      • DReal Intrinsic
      • DSinD Intrinsic
      • DTanD Intrinsic
      • Dtime Intrinsic (function)
      • FGet Intrinsic (function)
      • FGetC Intrinsic (function)
      • FloatI Intrinsic
      • FloatJ Intrinsic
      • FPut Intrinsic (function)
      • FPutC Intrinsic (function)
      • IDate Intrinsic (VXT)
      • IIAbs Intrinsic
      • IIAnd Intrinsic
      • IIBClr Intrinsic
      • IIBits Intrinsic
      • IIBSet Intrinsic
      • IIDiM Intrinsic
      • IIDInt Intrinsic
      • IIDNnt Intrinsic
      • IIEOr Intrinsic
      • IIFix Intrinsic
      • IInt Intrinsic
      • IIOr Intrinsic
      • IIQint Intrinsic
      • IIQNnt Intrinsic
      • IIShftC Intrinsic
      • IISign Intrinsic
      • IMax0 Intrinsic
      • IMax1 Intrinsic
      • IMin0 Intrinsic
      • IMin1 Intrinsic
      • IMod Intrinsic
      • INInt Intrinsic
      • INot Intrinsic
      • IZExt Intrinsic
      • JIAbs Intrinsic
      • JIAnd Intrinsic
      • JIBClr Intrinsic
      • JIBits Intrinsic
      • JIBSet Intrinsic
      • JIDiM Intrinsic
      • JIDInt Intrinsic
      • JIDNnt Intrinsic
      • JIEOr Intrinsic
      • JIFix Intrinsic
      • JInt Intrinsic
      • JIOr Intrinsic
      • JIQint Intrinsic
      • JIQNnt Intrinsic
      • JIShft Intrinsic
      • JIShftC Intrinsic
      • JISign Intrinsic
      • JMax0 Intrinsic
      • JMax1 Intrinsic
      • JMin0 Intrinsic
      • JMin1 Intrinsic
      • JMod Intrinsic
      • JNInt Intrinsic
      • JNot Intrinsic
      • JZExt Intrinsic
      • Kill Intrinsic (function)
      • Link Intrinsic (function)
      • QAbs Intrinsic
      • QACos Intrinsic
      • QACosD Intrinsic
      • QASin Intrinsic
      • QASinD Intrinsic
      • QATan Intrinsic
      • QATan2 Intrinsic
      • QATan2D Intrinsic
      • QATanD Intrinsic
      • QCos Intrinsic
      • QCosD Intrinsic
      • QCosH Intrinsic
      • QDiM Intrinsic
      • QExp Intrinsic
      • QExt Intrinsic
      • QExtD Intrinsic
      • QFloat Intrinsic
      • QInt Intrinsic
      • QLog Intrinsic
      • QLog10 Intrinsic
      • QMax1 Intrinsic
      • QMin1 Intrinsic
      • QMod Intrinsic
      • QNInt Intrinsic
      • QSin Intrinsic
      • QSinD Intrinsic
      • QSinH Intrinsic
      • QSqRt Intrinsic
      • QTan Intrinsic
      • QTanD Intrinsic
      • QTanH Intrinsic
      • Rename Intrinsic (function)
      • Secnds Intrinsic
      • Signal Intrinsic (function)
      • SinD Intrinsic
      • SnglQ Intrinsic
      • SymLnk Intrinsic (function)
      • System Intrinsic (function)
      • TanD Intrinsic
      • Time Intrinsic (VXT)
      • UMask Intrinsic (function)
      • Unlink Intrinsic (function)
      • ZExt Intrinsic
• Other Compilers
  • Dropping f2c Compatibility
  • Compilers Other Than f2c
• Other Languages
  • Tools and advice for interoperating with C and C++
    • C Interfacing Tools
    • Accessing Type Information in C
    • Generating Skeletons and Prototypes with f2c
    • C++ Considerations
    • Startup Code
• Installing GNU Fortran
  • Prerequisites
  • Problems Installing
    • General Problems
      • GNU C Required
      • Patching GNU CC
      • Building GNU CC Necessary
      • Missing strtoul or bsearch
      • Cleanup Kills Stage Directories
      • LANGUAGES Macro Ignored
    • System-specific Problems
    • Cross-compiler Problems
  • Changing Settings Before Building
    • Larger File Unit Numbers
    • Always Flush Output
    • Maximum Stackable Size
    • Floating-point Bit Patterns
    • Initialization of Large Aggregate Areas
    • Alpha Problems Fixed
  • Quick Start
  • Complete Installation
    • Unpacking
    • Merging Distributions
    • Where in the World Does Fortran (and GNU CC) Go?
    • Configuring GNU CC
    • Building GNU CC
      • Bootstrap Build
      • Straight Build
    • Pre-installation Checks
    • Installation of Binaries
    • Updating Your Info Directory
    • Missing tools?
      • Missing autoconf?
      • Missing bison?
      • Missing gperf?
      • Missing makeinfo?
  • Distributing Binaries
• Debugging and Interfacing
  • Main Program Unit (PROGRAM)
  • Procedures (SUBROUTINE and FUNCTION)
  • Functions (FUNCTION and RETURN)
  • Names
  • Common Blocks (COMMON)
  • Local Equivalence Areas (EQUIVALENCE)
  • Complex Variables (COMPLEX)
  • Arrays (DIMENSION)
  • Adjustable Arrays (DIMENSION)
  • Alternate Entry Points (ENTRY)
  • Alternate Returns (SUBROUTINE and RETURN)
  • Assigned Statement Labels (ASSIGN and GOTO)
  • Run-time Library Errors
• Collected Fortran Wisdom
  • Advantages Over f2c
    • Language Extensions
    • Compiler Options
    • Compiler Speed
    • Program Speed
    • Ease of Debugging
    • Character and Hollerith Constants
  • Block Data and Libraries
  • Loops
  • Working Programs
    • Not My Type
    • Variables Assumed To Be Zero
    • Variables Assumed To Be Saved
    • Unwanted Variables
    • Unused Arguments
    • Surprising Interpretations of Code
    • Aliasing Assumed To Work
    • Output Assumed To Flush
    • Large File Unit Numbers
  • Overly Convenient Command-line Options
  • Faster Programs
    • Aligned Data
    • Prefer Automatic Uninitialized Variables
    • Avoid f2c Compatibility
    • Use Submodel Options
• Known Causes of Trouble with GNU Fortran
  • Bugs Not In GNU Fortran
    • Signal 11 and Friends
    • Cannot Link Fortran Programs
    • Large Common Blocks
    • Debugger Problems
    • NeXTStep Problems
    • Stack Overflow
    • Nothing Happens
    • Strange Behavior at Run Time
    • Floating-point Errors
  • Actual Bugs We Haven't Fixed Yet
  • Missing Features
    • Better Source Model
    • Fortran 90 Support
    • Intrinsics in PARAMETER Statements
    • SELECT CASE on CHARACTER Type
    • RECURSIVE Keyword
    • Increasing Precision/Range
    • Popular Non-standard Types
    • Full Support for Compiler Types
    • Array Bounds Expressions
    • POINTER Statements
    • Sensible Non-standard Constructs
    • FLUSH Statement
    • Expressions in FORMAT Statements
    • Explicit Assembler Code
    • Q Edit Descriptor
    • Old-style PARAMETER Statements
    • TYPE and ACCEPT I/O Statements
    • STRUCTURE, UNION, RECORD, MAP
    • OPEN, CLOSE, and INQUIRE Keywords
    • ENCODE and DECODE
    • Suppressing Space Padding of Source Lines
    • Fortran Preprocessor
    • Bit Operations on Floating-point Data
    • POSIX Standard
    • Floating-point Exception Handling
    • Nonportable Conversions
    • Large Automatic Arrays
    • Support for Threads
    • Gracefully Handle Sensible Bad Code
    • Non-standard Conversions
    • Non-standard Intrinsics
    • Modifying DO Variable
    • Better Pedantic Compilation
    • Warn About Implicit Conversions
    • Invalid Use of Hollerith Constant
    • Dummy Array Without Dimensioning Dummy
    • Invalid FORMAT Specifiers
    • Ambiguous Dialects
    • Unused Labels
    • Informational Messages
    • Uninitialized Variables at Run Time
    • Bounds Checking at Run Time
    • Labels Visible to Debugger
  • Disappointments and Misunderstandings
    • Mangling of Names in Source Code
    • Multiple Definitions of External Names
    • Limitation on Implicit Declarations
  • Certain Changes We Don't Want to Make
    • Backslash in Constants
    • Initializing Before Specifying
    • Context-Sensitive Intrinsicness
    • Context-Sensitive Constants
    • Equivalence Versus Equality
    • Order of Side Effects
  • Warning Messages and Error Messages
• Open Questions
• Reporting Bugs
  • Have You Found a Bug?
  • Where to Report Bugs
  • How to Report Bugs
  • Sending Patches for GNU Fortran
• How To Get Help with GNU Fortran
• Adding Options
• Projects
  • Improve Efficiency
  • Better Optimization
  • Simplify Porting
  • More Extensions
  • Machine Model
  • Internals Documentation
  • Internals Improvements
  • Better Diagnostics
• Diagnostics
  • CMPAMBIG
  • EXPIMP
  • INTGLOB
  • LEX
  • GLOBALS
  • LINKFAIL
• Index

This document was generated on 21 July 1998 using the texi2html translator version 1.51a.