Read/Write after EOF marker (The GNU Fortran Compiler)

#### 5.1.21 Read/Write after EOF marker ¶

Some legacy codes rely on allowing `READ` or `WRITE` after the EOF file marker in order to find the end of a file. GNU Fortran normally rejects these codes with a run-time error message and suggests the user consider `BACKSPACE` or `REWIND` to properly position the file before the EOF marker. As an extension, the run-time error may be disabled using -std=legacy.