Firstly, thanks everyone and BrowserUK for the responses. Below are my responses to select parts of the follow-ups.

1.BrowserUK wrote:
However--and this is my recommendation--based on the pseudo-code you've posted which suggests the threads in question have no clean up to perform, nor any values to return, I would suggest upgrading to (the binary compatible) 5.8.9 and detaching the threads.

Well, I am to blame here. The pseudo-code, as expected, did not reveal much. This code below is declared before any thread is defined at the very top of the program. In effect, what I have done is to declare redirects for STDOUT and STDERR to a log file. And this is shared by all threads. 

# Opening log file.
# Redirecting OUTPUT and ERR to log file for all threads
open OUTPUT, '>>', "/usr/local/xxx/log/lease.log" or die $!;
open ERROR,  '>>', "/usr/local/xxx/log/lease.log"  or die $!;
STDOUT->fdopen( \*OUTPUT, 'w' ) or die $!;
STDERR->fdopen( \*ERROR,  'w' ) or die $!;

[download]

This simplifies my logging process but it, in turn creates problems when I shut the daemon down. Please keep in mind the the signal handler itself is shared by all threads which means each process has it's signal handlers defined. So what I needed to write in the signal handler was a clean closing of threads and file-handles, independent of the active thread. I thought about something similar to $timetoExit before posting here but did not know how to get beyond that point. The sleep 1 and next while --$sleepTime; was what I was looking for. Saw it. Loved it. Tested it with a mild tweak. And no more error messages.

2.BrowserUK wrote:
Detached threads are, by definition, fire-and-forget, so the earlier warnings were just wrong.

I did try detaching the thread. But the error message kept coming. And I was also worried about the open file handles in the async thread. I kept imagining the main thread receiving a SIGTERM while the sync thread was trying to write to the file-handle. I believe this is a possibility.

In reply to Re^2: Perl5.8.4 , threads - Killing the "async" kid by MonkeyMonk
in thread Perl5.8.4 , threads - Killing the "async" kid by MonkeyMonk

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