The $y defined-macro
($y) is intended to hold as its value the
base name of the controlling tty device (if
there is one). On BSD-derived systems this is a name such as the
following, but with the /dev/ prefix removed:
/dev/tty04
Defining TTYNAME enables sendmail to put this
information into $y:
APPENDDEF(`confENVDEF', `-DTTYNAME')
Note that TTYNAME is useful only for debugging
sendmail. The sendmail
program does not itself use $y for anything. Also
note that defining TTYNAME requires that your system support the
ttyname(2) system call. If you are running a
precompiled version of sendmail, you can
determine whether TTYNAME was defined by sending mail with the
-d35.9 debugging switch (-d35.9) and watching for $y to be
defined. You can tell because this line will be printed:
define(y as ttyp1)
