Runtime monitoring of listen queue in realtime

>From the documentation:
http://www.fastcgi.com/mod_fastcgi/docs/mod_fastcgi.html#FastCgiServer
-listen-queue-depth n (100)
The depth of listen() queue (also known as the backlog) shared by all of the instances of this application. A deeper listen queue
allows the server to cope with transient load fluctuations without rejecting requests; it does not increase throughput. Adding
additional application instances may increase throughput/performance, depending upon the application and the host.

Is there a way is monitor this listen queue at runtime in realtime? Is there a unix signal I can send to the FastCGI Process Manager
to print in the apache errors logs how deep the listen queue is?