These options affect the runtime behavior of programs compiled with GNU Fortran.
-fconvert=conversion
¶Specify the representation of data for unformatted files. Valid values for conversion on most systems are: ‘native’, the default; ‘swap’, swap between big- and little-endian; ‘big-endian’, use big-endian representation for unformatted files; ‘little-endian’, use little-endian representation for unformatted files.
On POWER systems which suppport -mabi=ieeelongdouble, there are additional options, which can be combined with others with commas. Those are
REAL(KIND=16)
.
REAL(KIND=16)
.
This option has an effect only when used in the main program.
The CONVERT
specifier and the GFORTRAN_CONVERT_UNIT environment
variable override the default specified by -fconvert.
-frecord-marker=length
¶Specify the length of record markers for unformatted files.
Valid values for length are 4 and 8. Default is 4.
This is different from previous versions of gfortran
,
which specified a default record marker length of 8 on most
systems. If you want to read or write files compatible
with earlier versions of gfortran
, use -frecord-marker=8.
-fmax-subrecord-length=length
¶Specify the maximum length for a subrecord. The maximum permitted value for length is 2147483639, which is also the default. Only really useful for use by the gfortran testsuite.
-fsign-zero
¶When enabled, floating point numbers of value zero with the sign bit set
are written as negative number in formatted output and treated as
negative in the SIGN
intrinsic. -fno-sign-zero does not
print the negative sign of zero values (or values rounded to zero for I/O)
and regards zero as positive number in the SIGN
intrinsic for
compatibility with Fortran 77. The default is -fsign-zero.