Squid running check

[Nickolay Pelov]

I noticed that squid checks if it is running by checking if pid file 
exists. I think it will be better to check if there is really process 
with that pid like:

if(kill(pid,0)==0){//squid is running
}else{ // no process
  //unlink the pid file
}
I don't know how kill is implemented in other operating systems but I'm 
sure that there is a way to check if process is running.