startupitem.pidfile options

[markd at macports.org]

James,

I don't fully understand the startupitem.pidfile options.  I think I've
got the documentation improved for startupitems, but like to improve it
some more.

Here are the current new docs on the options:

-------------------------------
Pidfile handling options:

none - The daemon is not to use a pidfile.
auto - The daemon generates its own pidfile.
manual - The daemon never generates a pidfile; the StartupItem must manage
the pidfile on its own.
clean - The daemon generates its own but will not delete it; the
StartupItem must delete it.
---------------------------------

Question 1)

I have a startupitem that creates the pidfile like this: 
'startupitem.start       "${nedimonitorbin} & echo \$! >
${nedimonitorpid}"'

I thought "manual" would be the best option.  But "manual" deleted my
pidfile when launchctl executed.  Why would that be?  Also, it sets
"<string>--pid=exec</string>"  in the .plist.  Is this correct?

I had to use the "clean" option, and it works fine, but I don't understand
why "manual" worked as it did, or why "clean" works since it says "the
startupitem must delete it" and mine doesn't.  Should the docs say
"daemondo must delete it", instead of "StartupItem must delete it"?

Question 2) 

none - This means that pidfile startupitem.pidfile disabled, correct? 
Same as not using the startupitem.pidfile keyword at all.


auto - This option deletes the pidfile as well, correct?

clean - "The daemon generates its own but will not delete it; the
StartupItem must delete it".  Why must implies the pid file should be
deleted.  Why?


Mark