⎕FERROR Return operating-system error

When a component-file operation fails because the operating system reports an error, APLX usually generates a FILE I/O ERROR (error code 17 in ⎕LER, or 6 9 in ⎕ET). The niladic system function ⎕FERROR returns a character vector with further information (if available) from the operating system about what caused the error. For example:

      ⎕FLIB 'C:\JIM\REGIONS'
The system cannot find the path specified.
FILE I/O ERROR
      ⎕FLIB 'C:\JIM\REGIONS'
      ^
      ⎕ET
6 9
     ⎕FERROR
The system cannot find the path specified.