Using GNU Fortran - GNU Compiler Collection

1 Using GNU FortranForgccversion (pre-release)(GCC)ThegfortranteamPublish ed by the Free Software Foundation51 Franklin Street, Fifth FloorBoston, MA 02110-1301, USAC opyrightc 1999-2022 Free Software Foundation, is granted to copy, distribute and/or modify this document under the terms ofthe GNU Free Documentation License, Version or any later version published by theFree Software Foundation; with the Invariant Sections being Funding Free Software , theFront-Cover Texts being (a) (see below), and with the Back-Cover Texts being (b) (seebelow). A copy of the license is included in the section entitled GNU Free DocumentationLicense .(a) The FSF s Front-Cover Text is:A GNU Manual(b) The FSF s Back-Cover Text is:You have freedom to copy and modify this GNU Manual, like GNU software. Copiespublished by the Free Software Foundation raise funds for GNU GNU Fortran2 GNU Fortran Command : Influencing runtime behavior with Reference4 Compiler General Public Free Documentation Free of Contents1 About GNU GNU Fortran and Fortran 95 Fortran 2003 Fortran 2008 Fortran 2018 I: Invoking GNU GNU Fortran Command Option Options controlling Fortran Enable and customize Options to request or suppress errors and Options for debugging your program or GNU Options for directory Influencing the linking Influencing runtime Options for code generation Options for interoperability with other Environment variables Runtime.

2 Influencing runtime behavior withenvironment Directory for scratch Unit number for standard Unit number for standard Unit number for standard Do not buffer I/O on all Do not buffer I/O onpreconnected Show location for runtime Print leading + where Separator for list Set endianness for unformatted Show backtrace on run-time Set buffer size forformatted GNU Fortran Set buffer size forunformatted II: Language Compiler KIND Type Internal representation of LOGICAL Evaluation of logical MAX and MIN intrinsics with REAL NaN Thread-safety of the runtime Data consistency and Files opened without an explicit ACTION= File operations on symbolic File format of unformatted sequential Asynchronous Extensions implemented in GNU Old-style kind Old-style variable Extensions to descriptor without count Commas Missing period Default widths forF,GandIformat I/O item BOZ literal Real array Unary Implicitly Hollerith constants Character Cray Argument list functions%VAL,%REFand% Read/Write after EOF Type variants for integer Extended math Form feed as TYPE as an alias for %LOC as an.

3 XOR. Bitwise logical Extended I/O Legacy PARAMETER Default Extensions not implemented in GNU Alternate complex function ( .. NAME=).. Mixed-Language Interoperability with Intrinsic Derived Types and Interoperable Global Interoperable Subroutines and Working with C Further Interoperability of Fortran with GNU Fortran Compiler ATTRIBUTES UNROLL BUILTIN IVDEP VECTOR NOVECTOR Non- Fortran Main Save command-line Set library option Set endian Set length of Enable floating point exception Set Naming and argument-passing Naming Argument passing GNU Fortran Compiler7 Coarray Type and enum ABI Function ABI Initialiation Finalization Querying the image Querying the maximalnumber of Query the status of Get an array of theindexes of the failed Get an array of theindexes of the stopped Registering Deregistering Query whether anallocatable or pointer component in a derived type coarray Sending data from a local

4 Image toa remote Getting data from a remote Sending data between Sending data from a localimage to a remote image with enhanced referencing Getting data from a remoteimage Using enhanced Sending data betweenremote images Using enhanced references on both Locking a lock Unlocking a lock Post an Wait that an event Query event All-image Barrier for selected Wait for completion ofsegment-memory Error termination with Error termination Mark the image failed andend its Atomic Atomic variable Atomic compare and Atomic Sending data to Collective maximum Collective minimum Collective summing Generic collective Intrinsic Introduction to intrinsic Abort the Absolute Checks file access Character inASCII collating Arccosine Arccosine function, Inverse hyperbolic cosine Left adjust a Right adjust a Imaginary part of complex Truncate to a whole Execute a routine after a given All values inMASK alongDIMare Status of an allocatable Bitwise logical Nearest whole Any value inMASK alongDIMis Arcsine Arcsine function, Inverse hyperbolic sine Status of a pointer or pointer/target Arctangent GNU Fortran Arctangent function, Arctangent Arctangent function.

5 Inverse hyperbolic tangent Atomic ADD Atomic bitwise AND Atomic compare and Setting a variable Atomic ADD operation with prior Atomic bitwise AND operation with Atomic bitwise OR operation with Atomic bitwise XOR operation with Atomic bitwise OR Obtaining the value of a variable Atomic bitwise OR Show a Bessel function of the first kind of order Bessel function of the first kind of order Bessel function of the first Bessel function of the second kind of order Bessel function of the second kind of order Bessel function of the second Bitwise greater than or equal Bitwise greater Bit size inquiry Bitwise less than or equal Bitwise less Bit test Status of a C Convert C into Fortran Convert C into Fortran procedure Obtain the C address of a Obtain the C address of an Size in bytes of an Integer ceiling Character conversion Change working Change access permissions of Complex conversion Copy a value to all images the current set Maximal value on the current set of Minimal value on the current set of Reduction of values on the current set of Sum of values on the current set of Get number of command Options passed to the Compiler version Complex conversion Complex conjugate Cosine Cosine function, Hyperbolic cosine Cotangent Cotangent function, Count CPU elapsed time in Circular shift elements of an Convert a time into a Date and time Double conversion Double complex conversion Significant binary digits Positive Dot product Double product Double real part Combined left Combined right Execution time subroutine (or function).

6 End-off shift elements of an Epsilon Error Error Error Execution time subroutine (or function).. Query whether a coarray event has Execute a shell Exit the program with Exponential Exponent Query dynamic type for Get the current time as a Read a single character in stream mode from Read a single character in stream Search an array for a Integer floor GNU Fortran Flush I/O unit(s).. File number Write a single character in stream mode to Write a single character in stream Fractional part of the model Frees Low level file positioning Get file Current stream Gamma Get last system error Get command line Get the entire command Get command line Get current working Get an environmental Get an environmental Group ID Get login Process ID User ID Convert time to GMT Get system host Largest number of a Euclidean distance Code inASCII collating Bitwise AND of array Bitwise logical Bitwise OR of array Get the number of command line Clear Bit Set Character-to-integer conversion Get current local time subroutine (day/month/year).

7 Bitwise logical exclusive Get the last system error Function that converts a cosubscript to animage Position of a substring within a Convert to integer Convert to 16-bit integer Convert to 64-bit integer Bitwise logical Bitwise XOR of array Integer pseudo-random Test whether an array is Test for end-of-file Test for end-of-record Whether a unit is a terminal Shift Shift bits Test for a Get current local time subroutine(hour/minutes/seconds).. Send a signal to a Kind of an Lower dimension bounds of an Lower codimension bounds of an Number of leading zero bits of an Length of a character Length of a character entity without trailing Lexical greater than or Lexical greater Create a hard Lexical less than or Lexical less Index of the last non-blank character in a Returns the address of a Natural logarithm Base 10 logarithm Logarithm of the Gamma Convert to logical Left shift Get file Convert time to local time Allocate dynamic Left justified Right justified matrix Maximum value of an argument Maximum exponent of a real Location of the maximum value within an Maximum value of an Time Time function (64-bit).

8 Merge Merge of bits under Minimum value of an argument Minimum exponent of a real Location of the minimum value within an Minimum value of an Remainder GNU Fortran Modulo Move allocation from one object to Move bits from one integer to Nearest representable New line Nearest whole Euclidean vector Logical Function that returns an disassociated Function that returns the number of Bitwise logical Pack an array into an array of rank Reduction with exclusive Print system error Number of bits Parity of the number of bits Decimal precision of a real Determine whether an optional dummy argument Product of array Base of a model Real pseudo-random Real pseudo-random Initialize a pseudo-random number Pseudo-random Initialize a pseudo-random number Decimal exponent Rank of a data Convert to real Rename a Repeated string Function to reshape an Reciprocal of the relative Right shift Query dynamic types for Scale a real Scan a string for the presence of a set of Time CPU time Choose character Choose integer Choose real Set the exponent of the Determine the shape of an Right shift with Left Right Sign copying Signal handling subroutine (or function).

9 Sine Sine function, Hyperbolic sine Determine the size of an Size in bytes of an Sleep for the specified number of Smallest distance between two numbers of a Add a dimension to an Square-root Reinitialize the random number Get file Storage size in Sum of array Create a symbolic Execute a shell Time Tangent Tangent function, Hyperbolic tangent Function that returns the cosubscript index ofthis Time Time function (64-bit).. Smallest positive number of a real Number of trailing zero bits of an Transfer bit Transpose an array of rank Remove trailing blank characters of a Get the name of a terminal Upper dimension bounds of an Upper codimension bounds of an Set the file creation Remove a file from the file Unpack an array of rank one into an Scan a string for characters not a given Bitwise logical exclusive GNU Fortran Compiler9 Intrinsic IEEE modules:IEEE_EXCEPTIONS,IEEE_ARITHMETIC, OpenMP OpenACC to GNU General Public Free Documentation : How to use this License for your Free 1: Introduction11 IntroductionThis manual documents the use ofgfortran, the GNU Fortran Compiler .

10 You can find inthis manual how to invokegfortran, as well as its features and :This document, and the Compiler it describes, are still under efforts are made to keep it up-to-date, it might not accurately reflect the status ofthe most recent GNU Fortran About GNU FortranThe GNU Fortran Compiler is the successor tog77, the Fortran 77 front end included inGCC prior to version 4 (released in 2005). While it is backward-compatible with mostg77extensions and command-line options,gfortranis a completely new implemention designedto support more modern dialects of Fortran . GNU Fortran implements the Fortran 77, 90and 95 standards completely, most of the Fortran 2003 and 2008 standards, and somefeatures from the 2018 standard. It also implements several extensions including OpenMPand OpenACC support for parallel GNU Fortran Compiler passes theNIST Fortran 77 Test Suite, and produces accept-able results on theLAPACK Test Suite.