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. The
CONVERTspecifier 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
SIGNintrinsic. -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
SIGNintrinsic for compatibility with Fortran 77. The default is -fsign-zero.