KILL!

[Bill Campbell]

On Thu, Feb 01, 2007, Matthew Carpenter wrote:
>Any C programmers out there have a good understanding of the ins and outs of 
>GLIB's "kill" function?
>
>Specifically, it indicates that if the SIGNAL sent is 0, no signal is actually 
>sent but error checking is processed.  Quoted from the man page:
>
>	int kill(pid_t pid, int sig);
><snip>
> "If sig is 0, then no signal is sent, but error checking is still performed."
>
>What the freak does that mean!?  Why would you call kill without actually 
>wanting to send a signal!?  Why did the chicken cross the road!?  Was it just 
>to see if he could!  little prick.  er...  chick.

The ``kill -0'' is generally used to test the existence of a
process, and is often used in conjunction with a *.pid file to
see if daemons are functioning.  In shell speak this might be:

pidfile="..." point to a daemon's daemonname.pid file

active='no'
test -e $pidfile && kill -0 `cat $pidfile` && {
	active='yes'
}

Bill
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