title: Detect the number of cores on windows
body: <p>If I am running R on linux or on a mac, I can detect the number of available cores using <code>multicore:::detectCores()</code>.  However, there's no windows version of the multicore functions, so I can't use this technique on windows.</p>
  
  <p>How can I programmatically detect the number of cores on a windows machine, from within R?</p>