All open files are closed with default sta at normal program termination. Regardless of the specified sta, scratch files, when closed, are always deleted.
Execution of a CLOSE statement specifying a unit that does not exist, or a unit that has no file connected to it, has no effect.
Execution of a CLOSE statement specifying a unit zero (standard error) is not allowed, but you can reopen it to some other file.
The unit or file disconnected by the execution of a CLOSE statement can be connected again to the same, or a different, file or unit.
For tape I/O, use the TOPEN() routines.