Default widths for F/G/I format descriptors (The GNU Fortran Compiler)

#### 5.1.7 Default widths for ‘`F`’, ‘`G`’ and ‘`I`’ format descriptors ¶

To support legacy codes, GNU Fortran allows width to be omitted from format specifications if and only if `-fdec-format-defaults` is given on the command line. Default widths are used. This is considered non-conforming code and is discouraged.

           REAL :: value1
           INTEGER :: value2
           WRITE(*,10) value1, value1, value2
    10     FORMAT ('F, G, I')