Using and Porting GNU Fortran

Introduction
GNU GENERAL PUBLIC LICENSE
- Preamble
- How to Apply These Terms to Your New Programs
GNU Free Documentation License
- ADDENDUM: How to use this License for your documents
Contributors to GNU Fortran
Funding Free Software
Funding GNU Fortran
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
- Conformance
- Notation Used in This Chapter
- Fortran Terms and Concepts
- Characters, Lines, and Execution Sequence
- Data Types and Constants
- Expressions
  - The %LOC() Construct
- Specification Statements
  - NAMELIST Statement
  - DOUBLE COMPLEX Statement
- Control Statements
- Functions and Subroutines
- Scope and Classes of Symbolic Names
  - Underscores in Symbol Names
- I/O
- Fortran 90 Features
Other Dialects
- Source Form
- 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
The GNU Fortran Compiler
- Compiler Limits
- Run-time Environment Limits
- Compiler Types
- Compiler Constants
- Compiler Intrinsics
  - Intrinsic Groups
  - Other Intrinsics
Other Compilers
- Dropping f2c Compatibility
- Compilers Other Than f2c
Other Languages
- Tools and advice for interoperating with C and C++
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
- Block Data and Libraries
- Loops
- Working Programs
- Overly Convenient Command-line Options
- Faster Programs
Known Causes of Trouble with GNU Fortran
- Bugs Not In GNU Fortran
- Known Bugs In GNU Fortran
- Missing Features
- Disappointments and Misunderstandings
- Certain Changes We Don't Want to Make
- Warning Messages and Error Messages
Open Questions
Reporting Bugs
- Have You Found a Bug?
- Where to Report Bugs
- How to Report Bugs
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
Front End
- Overview of Sources
- Overview of Translation Process
- Philosophy of Code Generation
- Two-pass Design
  - Two-pass Code
  - Why Two Passes
- Challenges Posed
- Transforming Statements
- Transforming Expressions
- Internal Naming Conventions
Diagnostics
- CMPAMBIG
- EXPIMP
- INTGLOB
- LEX
- GLOBALS
- LINKFAIL
- Y2KBAD
Index

This manual documents how to run, install and port g77, as well as its new features and incompatibilities, and how to report bugs. It corresponds to the GCC-3.1 version of g77.

Short Contents

Table of Contents

Introduction