title: Is random_shuffle threadsafe? and using rand_r if it is not
body: <p>Is std::random_shuffle threadsafe? I presume not since the regular rand() is not threadsafe. If that is the case, how would I use rand_r with random_shuffle so that I can give each thread a unique seed. I've seen examples of using custom random generators with random_shuffle, but it is still unclear to me.</p>
  
  <p>Thanks.</p>