title: How to check whether specified PID is currently running without invoking ps from PHP?
body: <p>We would like to check if a specified process is currently running via PHP.</p>
  
  <p>We would like to simply supply a PID and see if it is currently executing or not.</p>
  
  <p>Does PHP have an internal function that would give us this information or do we have to parse it out of "ps" output?</p>