eof - Check for end-of-file condition on open file
Returns 1 if an end-of-file condition has occurred on fileId,
FileId must have been the return
value from a previous call to open, or it may be stdin,
stdout, or stderr to refer to one of the standard I/O
Copyright © 1993 The Regents of the University of California.
Copyright © 1994 Sun Microsystems, Inc.
Copyright © 1995 Roger E. Critchlow Jr.