Causes a file (by default, \fBofp\-discover.pid\fR) to be created indicating
the PID of the running process. If \fIpidfile\fR is not specified, or
if it does not begin with \fB/\fR, then it is created in
-\fB@rundir@\fR.
+\fB@RUNDIR@\fR.
The \fIpidfile\fR is created when \fBofp\-discover\fR detaches, so
this this option has no effect when one of \fB--exit-without-bind\fR,