Error_Recovery

 The 'error_recovery' specifies the action  to  be  taken  if  an
 error occurs during execution of the routine.  By default, after
 the first error, the error message is printed and  execution  is
 stopped.

 Execution of the CLOSE procedure causes the system to close  the
 file  and,  if the file is internal, to delete it.  Each file is
 automatically closed when control passes from the block in which
 it is declared.

 You cannot close  a  file  that  has  not  been  opened  (either
 explicitly  by  the OPEN procedure, or implicitly by the EXTEND,
 RESET, or REWRITE procedure).  If you attempt to  close  a  file
 that was never opened, an error occurs.

 The  file  can  be  in  any  mode  (inspection,  generation,  or
 undefined)  before  the CLOSE procedure is called.  Execution of
 CLOSE sets the mode to undefined.