f2c - Convert Fortran 77 to C or C++
f2c [ option ... ] file ...
F2c converts Fortran 77 source code in files with names ending in ‘.f’
or ‘.F’ to C (or C++) source files in the current directory, with ‘.c’
substituted for the final ‘.f’ or ‘.F’. If no Fortran files are named,
f2c reads Fortran from standard input and writes C on standard output.
File names that end with ‘.p’ or ‘.P’ are taken to be prototype files,
as produced by option ‘-P’, and are read first.
The following options have the same meaning as in f77(1).
-C Compile code to check that subscripts are within declared array
-I2 Render INTEGER and LOGICAL as short, INTEGER∗4 as long int.
Assume the default libF77 and libI77: allow only INTEGER∗4 (and
no LOGICAL) variables in INQUIREs. Option ‘-I4’ confirms the
default rendering of INTEGER as long int.
-Idir Look for a non-absolute include file first in the directory of
the current input file, then in directories specified by -I
options (one directory per option). Options -I2 and -I4 have
precedence, so, e.g., a directory named 2 should be specified by
Compile DO loops that are performed at least once if reached.
(Fortran 77 DO loops are not performed at all if the upper limit
is smaller than the lower limit.)
-U Honor the case of variable and external names. Fortran keywords
must be in lower case.
-u Make the default type of a variable ‘undefined’ rather than
using the default Fortran rules.
-w Suppress all warning messages, or, if the option is ‘-w66’, just
Fortran 66 compatibility warnings.
The following options are peculiar to f2c.
-A Produce ANSI C (default, starting 20020621). For old-style C,
use option -K.
-a Make local variables automatic rather than static unless they
appear in a DATA, EQUIVALENCE, NAMELIST, or SAVE statement.
-C++ Output C++ code.
-c Include original Fortran source as comments.
-cd Do not recognize cdabs, cdcos, cdexp, cdlog, cdsin, and cdsqrt
as synonyms for the double complex intrinsics zabs, zcos, zexp,
zlog, zsin, and zsqrt, respectively, nor dreal as a synonym for
-ddir Write ‘.c’ files in directory dir instead of the current
-E Declare uninitialized COMMON to be Extern (overridably defined
in f2c.h as extern).
-ec Place uninitialized COMMON blocks in separate files: COMMON
/ABC/ appears in file abc_com.c. Option ‘-e1c’ bundles the
separate files into the output file, with comments that give an
unbundling sed(1) script.
-ext Complain about f77(1) extensions.
-f Assume free-format input: accept text after column 72 and do not
pad fixed-format lines shorter than 72 characters with blanks.
-72 Treat text appearing after column 72 as an error.
-g Include original Fortran line numbers in #line lines.
-h Emulate Fortran 66’s treatment of Hollerith: try to align
character strings on word (or, if the option is ‘-hd’, on
-i2 Similar to -I2, but assume a modified libF77 and libI77
(compiled with -Df2c_i2), so INTEGER and LOGICAL variables may
be assigned by INQUIRE and array lengths are stored in short
-i90 Do not recognize the Fortran 90 bit-manipulation intrinsics
btest, iand, ibclr, ibits, ibset, ieor, ior, ishft, and ishftc.
-kr Use temporary values to enforce Fortran expression evaluation
where K&R (first edition) parenthesization rules allow
rearrangement. If the option is ‘-krd’, use double precision
temporaries even for single-precision operands.
-P Write a file.P of ANSI (or C++) prototypes for definitions in
each input file.f or file.F. When reading Fortran from standard
input, write prototypes at the beginning of standard output.
Option -Ps implies -P and gives exit status 4 if rerunning f2c
may change prototypes or declarations.
-p Supply preprocessor definitions to make common-block members
look like local variables.
-R Do not promote REAL functions and operations to DOUBLE
PRECISION. Option ‘-!R’ confirms the default, which imitates
-r Cast REAL arguments of intrinsic functions and values of REAL
functions (including intrinsics) to REAL.
-r8 Promote REAL to DOUBLE PRECISION, COMPLEX to DOUBLE COMPLEX.
-s Preserve multidimensional subscripts. Suppressed by option ‘-C’
-Tdir Put temporary files in directory dir.
Dynamically initialize local variables, except those appearing
in SAVE or DATA statements, with values that may help find
references to uninitialized variables. For example, with IEEE
arithmetic, initialize local floating-point variables to
-w8 Suppress warnings when COMMON or EQUIVALENCE forces odd-word
alignment of doubles.
-Wn Assume n characters/word (default 4) when initializing numeric
variables with character data.
-z Do not implicitly recognize DOUBLE COMPLEX.
-!bs Do not recognize backslash escapes (\", \’, \0, \\, \b, \f, \n,
\r, \t, \v) in character strings.
-!c Inhibit C output, but produce -P output.
i-!I Reject include statements.
-!i8 Disallow INTEGER*8 , or, if the option is ‘-!i8const’, permit
INTEGER*8 but do not promote integer constants to INTEGER*8 when
they involve more than 32 bits.
-!it Don’t infer types of untyped EXTERNAL procedures from use as
parameters to previously defined or prototyped procedures.
-!P Do not attempt to infer ANSI or C++ prototypes from usage.
Print the version number of f2c
The resulting C invokes the support routines of f77; object code should
be loaded by f77 or with ld(1) or cc(1) options -lF77 -lI77 -lm.
Calling conventions are those of f77: see the reference below.
*.c output file
static link intrinsic and I/O library
static link intrinsic and I/O library for use with files
translated using the -i2 f2c option
shared object intrinsic and I/O library
shared object intrinsic and I/O library for use with files
translated using the -i2 f2c option
S. I. Feldman and P. J. Weinberger, ‘A Portable Fortran 77
Compiler’, UNIX Time Sharing System Programmers Manual, Tenth
Edition, Volume 2, AT&T Bell Laboratories, 1990.
The diagnostics produced by f2c are intended to be self-explanatory.
Floating-point constant expressions are simplified in the floating-
point arithmetic of the machine running f2c, so they are typically
accurate to at most 16 or 17 decimal places.
Untypable EXTERNAL functions are declared int.
There is no notation for INTEGER*8 constants.
Some intrinsic functions do not yet work with INTEGER*8 .