DOS Fn 10H: Close File via FCB

                                                         Compatibility: 1.0+ 
 Expects: AH    10H
          DS:DX address of an open FCB
 Returns: AL    0    if file closed without error
                0ffH if file was not found where it was upon fn 0fH (open)
    Info: Closes a file that was opened using an FCB.

          The file entry must be in its original place in the current
          default directory of the disk from which it was opened.

          If the file IS found, the directory is updated, the file buffers
          are flushed, and AL=00H upon return.

          If the file IS NOT found, the directory is not updated, a variety
          of unsavory things happen, and AL=0ffH upon return.

See Also: Fn 3eh (close file via handle)
          FCB File I/O
          Handle-Oriented File I/O
          Directory and File Functions
          DOS Functions