title: Thread-safety of C standard library on OS X
body: <p>Is there a definitive list of functions that are thread-safe in Mac OS X's implementation of the C standard library?</p>
  
  <p>There is a good answer <a href="https://stackoverflow.com/a/468105/216724">here</a> with regards to <code>glibc</code> and <code>f*()</code> functions specifically, but I have failed to find any such resource with respect to OS X. Is there such a thing?</p>
  
  <p>For example, are <code>strptime()</code> and <code>strftime()</code> thread-safe? <code>printf()</code>? These are some that may have internal buffers that I would not want to mess up. :)</p>