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PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
FORT77(1P) POSIX Programmer's Manual FORT77(1P)
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
fort77 — FORTRAN compiler (FORTRAN)
fort77 [−c] [−g] [−L directory]... [−O optlevel] [−o outfile] [−s]
[−w] operand...
The fort77 utility is the interface to the FORTRAN compilation
system; it shall accept the full FORTRAN-77 language defined by the
ANSI X3.9‐1978 standard. The system conceptually consists of a
compiler and link editor. The files referenced by operands are
compiled and linked to produce an executable file. It is unspecified
whether the linking occurs entirely within the operation of fort77;
some implementations may produce objects that are not fully resolved
until the file is executed.
If the −c option is present, for all pathname operands of the form
file.f, the files:
$(basename pathname.f).o
shall be created or overwritten as the result of successful
compilation. If the −c option is not specified, it is unspecified
whether such .o files are created or deleted for the file.f operands.
If there are no options that prevent link editing (such as −c) and
all operands compile and link without error, the resulting executable
file shall be written into the file named by the −o option (if
present) or to the file a.out. The executable file shall be created
as specified in the System Interfaces volume of POSIX.1‐2008, except
that the file permissions shall be set to: S_IRWXO | S_IRWXG |
S_IRWXU
and that the bits specified by the umask of the process shall be
cleared.
The fort77 utility shall conform to the Base Definitions volume of
POSIX.1‐2008, Section 12.2, Utility Syntax Guidelines, except that:
* The −l library operands have the format of options, but their
position within a list of operands affects the order in which
libraries are searched.
* The order of specifying the multiple −L options is significant.
* Conforming applications shall specify each option separately;
that is, grouping option letters (for example, −cg) need not be
recognized by all implementations.
The following options shall be supported:
−c Suppress the link-edit phase of the compilation, and do not
remove any object files that are produced.
−g Produce symbolic information in the object or executable
files; the nature of this information is unspecified, and
may be modified by implementation-defined interactions with
other options.
−s Produce object or executable files, or both, from which
symbolic and other information not required for proper
execution using the exec family of functions defined in the
System Interfaces volume of POSIX.1‐2008 has been removed
(stripped). If both −g and −s options are present, the
action taken is unspecified.
−o outfile
Use the pathname outfile, instead of the default a.out, for
the executable file produced. If the −o option is present
with −c, the result is unspecified.
−L directory
Change the algorithm of searching for the libraries named
in −l operands to look in the directory named by the
directory pathname before looking in the usual places.
Directories named in −L options shall be searched in the
specified order. At least ten instances of this option
shall be supported in a single fort77 command invocation.
If a directory specified by a −L option contains a file
named libf.a, the results are unspecified.
−O optlevel
Specify the level of code optimization. If the optlevel
option-argument is the digit '0', all special code
optimizations shall be disabled. If it is the digit '1',
the nature of the optimization is unspecified. If the −O
option is omitted, the nature of the system's default
optimization is unspecified. It is unspecified whether code
generated in the presence of the −O 0 option is the same as
that generated when −O is omitted. Other optlevel values
may be supported.
−w Suppress warnings.
Multiple instances of −L options can be specified.
An operand is either in the form of a pathname or the form −l
library. At least one operand of the pathname form shall be
specified. The following operands shall be supported:
file.f The pathname of a FORTRAN source file to be compiled and
optionally passed to the link editor. The filename operand
shall be of this form if the −c option is used.
file.a A library of object files typically produced by ar, and
passed directly to the link editor. Implementations may
recognize implementation-defined suffixes other than .a as
denoting object file libraries.
file.o An object file produced by fort77 −c and passed directly to
the link editor. Implementations may recognize
implementation-defined suffixes other than .o as denoting
object files.
The processing of other files is implementation-defined.
−l library
(The letter ell.) Search the library named:
liblibrary.a
A library is searched when its name is encountered, so the
placement of a −l operand is significant. Several standard
libraries can be specified in this manner, as described in
the EXTENDED DESCRIPTION section. Implementations may
recognize implementation-defined suffixes other than .a as
denoting libraries.
Not used.
The input file shall be one of the following: a text file containing
FORTRAN source code; an object file in the format produced by fort77
−c; or a library of object files, in the format produced by archiving
zero or more object files, using ar. Implementations may supply
additional utilities that produce files in these formats. Additional
input files are implementation-defined.
A <tab> encountered within the first six characters on a line of
source code shall cause the compiler to interpret the following
character as if it were the seventh character on the line (that is,
in column 7).
The following environment variables shall affect the execution of
fort77:
LANG Provide a default value for the internationalization
variables that are unset or null. (See the Base Definitions
volume of POSIX.1‐2008, Section 8.2, Internationalization
Variables for the precedence of internationalization
variables used to determine the values of locale
categories.)
LC_ALL If set to a non-empty string value, override the values of
all the other internationalization variables.
LC_CTYPE Determine the locale for the interpretation of sequences of
bytes of text data as characters (for example, single-byte
as opposed to multi-byte characters in arguments and input
files).
LC_MESSAGES
Determine the locale that should be used to affect the
format and contents of diagnostic messages written to
standard error.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
TMPDIR Determine the pathname that should override the default
directory for temporary files, if any.
Default.
Not used.
The standard error shall be used only for diagnostic messages. If
more than one file operand ending in .f (or possibly other
unspecified suffixes) is given, for each such file:
"%s:\n", <file>
may be written to allow identification of the diagnostic message with
the appropriate input file.
This utility may produce warning messages about certain conditions
that do not warrant returning an error (non-zero) exit value.
Object files, listing files, and executable files shall be produced
in unspecified formats.
Standard Libraries
The fort77 utility shall recognize the following −l operand for the
standard library:
−l f This library contains all functions referenced in the
ANSI X3.9‐1978 standard. This operand shall not be required
to be present to cause a search of this library.
In the absence of options that inhibit invocation of the link editor,
such as −c, the fort77 utility shall cause the equivalent of a −l f
operand to be passed to the link editor as the last −l operand,
causing it to be searched after all other object files and libraries
are loaded.
It is unspecified whether the library libf.a exists as a regular
file. The implementation may accept as −l operands names of objects
that do not exist as regular files.
External Symbols
The FORTRAN compiler and link editor shall support the significance
of external symbols up to a length of at least 31 bytes; case folding
is permitted. The action taken upon encountering symbols exceeding
the implementation-defined maximum symbol length is unspecified.
The compiler and link editor shall support a minimum of 511 external
symbols per source or object file, and a minimum of 4095 external
symbols total. A diagnostic message is written to standard output if
the implementation-defined limit is exceeded; other actions are
unspecified.
The following exit values shall be returned:
0 Successful compilation or link edit.
>0 An error occurred.
When fort77 encounters a compilation error, it shall write a
diagnostic to standard error and continue to compile other source
code operands. It shall return a non-zero exit status, but it is
implementation-defined whether an object module is created. If the
link edit is unsuccessful, a diagnostic message shall be written to
standard error, and fort77 shall exit with a non-zero status.
The following sections are informative.
None.
The following usage example compiles xyz.f and creates the executable
file foo:
fort77 −o foo xyz.f
The following example compiles xyz.f and creates the object file
xyz.o:
fort77 −c xyz.f
The following example compiles xyz.f and creates the executable file
a.out:
fort77 xyz.f
The following example compiles xyz.f, links it with b.o, and creates
the executable a.out:
fort77 xyz.f b.o
The name of this utility was chosen as fort77 to parallel the
renaming of the C compiler. The name f77 was not chosen to avoid
problems with historical implementations. The ANSI X3.9‐1978 standard
was selected as a normative reference because the ISO/IEC version of
FORTRAN-77 has been superseded by the ISO/IEC 1539:1991 standard.
The file inclusion and symbol definition #define mechanisms used by
the c99 utility were not included in this volume of POSIX.1‐2008—even
though they are commonly implemented—since there is no requirement
that the FORTRAN compiler use the C preprocessor.
The −onetrip option was not included in this volume of POSIX.1‐2008,
even though many historical compilers support it, because it is
derived from FORTRAN-66; it is an anachronism that should not be
perpetuated.
Some implementations produce compilation listings. This aspect of
FORTRAN has been left unspecified because there was controversy
concerning the various methods proposed for implementing it: a −V
option overlapped with historical vendor practice and a naming
convention of creating files with .l suffixes collided with
historical lex file naming practice.
There is no −I option in this version of this volume of POSIX.1‐2008
to specify a directory for file inclusion. An INCLUDE directive has
been a part of the Fortran-90 discussions, but an interface
supporting that standard is not in the current scope.
It is noted that many FORTRAN compilers produce an object module even
when compilation errors occur; during a subsequent compilation, the
compiler may patch the object module rather than recompiling all the
code. Consequently, it is left to the implementor whether or not an
object file is created.
A reference to MIL-STD-1753 was removed from an early proposal in
response to a request from the POSIX FORTRAN-binding standard
developers. It was not the intention of the standard developers to
require certification of the FORTRAN compiler, and
IEEE Std 1003.9‐1992 does not specify the military standard or any
special preprocessing requirements. Furthermore, use of that document
would have been inappropriate for an international standard.
The specification of optimization has been subject to changes through
early proposals. At one time, −O and −N were Booleans: optimize and
do not optimize (with an unspecified default). Some historical
practice led this to be changed to:
−O 0 No optimization.
−O 1 Some level of optimization.
−O n Other, unspecified levels of optimization.
It is not always clear whether ``good code generation'' is the same
thing as optimization. Simple optimizations of local actions do not
usually affect the semantics of a program. The −O 0 option has been
included to accommodate the very particular nature of scientific
calculations in a highly optimized environment; compilers make
errors. Some degree of optimization is expected, even if it is not
documented here, and the ability to shut it off completely could be
important when porting an application. An implementation may treat −O
0 as ``do less than normal'' if it wishes, but this is only
meaningful if any of the operations it performs can affect the
semantics of a program. It is highly dependent on the implementation
whether doing less than normal is logical. It is not the intent of
the −O 0 option to ask for inefficient code generation, but rather to
assure that any semantically visible optimization is suppressed.
The specification of standard library access is consistent with the C
compiler specification. Implementations are not required to have
/usr/lib/libf.a, as many historical implementations do, but if not
they are required to recognize f as a token.
External symbol size limits are in normative text; conforming
applications need to know these limits. However, the minimum maximum
symbol length should be taken as a constraint on a conforming
application, not on an implementation, and consequently the action
taken for a symbol exceeding the limit is unspecified. The minimum
size for the external symbol table was added for similar reasons.
The CONSEQUENCES OF ERRORS section clearly specifies the behavior of
the compiler when compilation or link-edit errors occur. The behavior
of several historical implementations was examined, and the choice
was made to be silent on the status of the executable, or a.out, file
in the face of compiler or linker errors. If a linker writes the
executable file, then links it on disk with lseek()s and write()s,
the partially linked executable file can be left on disk and its
execute bits turned off if the link edit fails. However, if the
linker links the image in memory before writing the file to disk, it
need not touch the executable file (if it already exists) because the
link edit fails. Since both approaches are historical practice, a
conforming application shall rely on the exit status of fort77,
rather than on the existence or mode of the executable file.
The −g and −s options are not specified as mutually-exclusive.
Historically, these two options have been mutually-exclusive, but
because both are so loosely specified, it seemed appropriate to leave
their interaction unspecified.
The requirement that conforming applications specify compiler options
separately is to reserve the multi-character option name space for
vendor-specific compiler options, which are known to exist in many
historical implementations. Implementations are not required to
recognize, for example, −gc as if it were −g −c; nor are they
forbidden from doing so. The SYNOPSIS shows all of the options
separately to highlight this requirement on applications.
Echoing filenames to standard error is considered a diagnostic
message because it would otherwise be difficult to associate an error
message with the erring file. They are described with ``may'' to
allow implementations to use other methods of identifying files and
to parallel the description in c99.
A compilation system based on the ISO/IEC 1539:1991 standard may be
considered for a future version; it may have a different utility name
from fort77.
ar(1p), asa(1p), c99(1p), umask(1p)
The Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment
Variables, Section 12.2, Utility Syntax Guidelines
The System Interfaces volume of POSIX.1‐2008, exec(1p)
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 FORT77(1P)
Pages that refer to this page: ar(1p), asa(1p), ctags(1p), strip(1p)