PGI Fortran Reference Guide Version 2015 PGI Compilers and Tools TABLE OF CONTENTS Preface............................................................................................................................................................................... xxiv Audience Description......................................................................................................................................................xxiv Compatibility and Conformance to Standards................................................................................................................xxiv Organization.....................................................................................................................................................................xxv Hardware and Software Constraints.............................................................................................................................. xxvi Conventions.................................................................................................................................................................... xxvi Related Publications....................................................................................................................................................... xxvi Chapter 1. Language Overview............................................................................................................................................1 1.1. Elements of a Fortran Program Unit...........................................................................................................................1 1.1.1. Fortran Statements.............................................................................................................................................. 1 1.1.2. Free and Fixed Source........................................................................................................................................1 1.1.3. Statement Ordering..............................................................................................................................................2 1.2. The Fortran Character Set..........................................................................................................................................3 1.3. Free Form Formatting................................................................................................................................................. 4 1.4. Fixed Formatting..........................................................................................................................................................4 1.4.1. Column Formatting.............................................................................................................................................. 5 1.4.2. Fixed Format Label Field.....................................................................................................................................5 1.4.3. Fixed Format Continuation Field......................................................................................................................... 5 1.4.4. Fixed Format Statement Field.............................................................................................................................5 1.4.5. Fixed Format Debug Statements........................................................................................................................ 6 1.4.6. Tab Formatting.....................................................................................................................................................6 1.4.7. Fixed Input File Format Summary.......................................................................................................................6 1.5. Include Fortran Source Files.......................................................................................................................................7 1.6. Components of Fortran Statements............................................................................................................................7 1.6.1. Symbolic Names..................................................................................................................................................7 1.7. Expressions..................................................................................................................................................................8 1.7.1. Forming Expressions........................................................................................................................................... 8 1.7.2. Expression Precedence Rules.............................................................................................................................8 1.7.3. Arithmetic Expressions........................................................................................................................................ 9 1.7.4. Relational Expressions...................................................................................................................................... 11 1.7.5. Logical Expressions...........................................................................................................................................11 1.7.6. Character Expressions.......................................................................................................................................12 1.7.7. Character Concatenation................................................................................................................................... 12 1.8. Symbolic Name Scope..............................................................................................................................................12 1.9. Assignment Statements.............................................................................................................................................12 1.9.1. Arithmetic Assignment....................................................................................................................................... 13 1.9.2. Logical Assignment............................................................................................................................................13 1.9.3. Character Assignment....................................................................................................................................... 14 1.10. Listing Controls........................................................................................................................................................14 1.11. OpenMP Directives..................................................................................................................................................15 PGI Fortran Reference Guide ii Chapter 2. Fortran Data Types...........................................................................................................................................16 2.1. Intrinsic Data Types...................................................................................................................................................16 2.1.1. Kind Parameter..................................................................................................................................................16 2.1.2. Number of Bytes Specification.......................................................................................................................... 17 2.2. Constants...................................................................................................................................................................19 2.2.1. Integer Constants...............................................................................................................................................19 2.2.2. Binary, Octal and Hexadecimal Constants........................................................................................................19 2.2.3. Real Constants.................................................................................................................................................. 20 2.2.4. Double Precision Constants.............................................................................................................................. 20 2.2.5. Complex Constants............................................................................................................................................21 2.2.6. Double Complex Constants...............................................................................................................................21 2.2.7. Logical Constants.............................................................................................................................................. 21 2.2.8. Character Constants..........................................................................................................................................21 2.2.9. Parameter Constants.........................................................................................................................................22 2.3. Structure Constructors...............................................................................................................................................22 2.4. Derived Types............................................................................................................................................................23 2.5. Deferred Type Parameters........................................................................................................................................24