2.8 Influencing runtime behavior
These options affect the runtime behavior of programs compiled with GNU Fortran.
- Specify the representation of data for unformatted files. Valid
values for conversion 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.
This option has an effect only when used in the main program.
CONVERT specifier and the GFORTRAN_CONVERT_UNIT environment
variable override the default specified by -fconvert.
- 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.
- 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.
- 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.