NAME
	  ctermid - generate file name for terminal
SYNTAX
	  #include <stdio.h>
	  char *ctermid	(s)
	  char *s;
DESCRIPTION
	  Ctermid generates the	path name of the controlling terminal
	  for the current process, and stores it in a string.
	  If s is a NULL pointer, the string is	stored in an internal
	  static area, the contents of which are overwritten at	the
	  next call to ctermid,	and the	address	of which is returned.
	  Otherwise, s is assumed to point to a	character array	of at
	  least	L_ctermid elements; the	path name is placed in this
	  array	and the	value of s is returned.	 The constant
	  L_ctermid is defined in the <stdio.h>	header file.
     NOTES
	  The difference between ctermid and ttyname(3C) is that
	  ttyname must be handed a file	descriptor and returns the
	  actual name of the terminal associated with that file
	  descriptor, while ctermid returns a string (/dev/tty)	that
	  will refer to	the terminal if	used as	a file name.  Thus
	  ttyname is useful only if the	process	already	has at least
	  one file open	to a terminal.
SEE ALSO
	  ttyname(3C).