title: implicit declaration of function ‘usleep’
body: <p>So i've been looking stuff about <code>usleep()</code> and all I have found to get rid of this is <code>#define</code> which i have done... Any ohter suggestion? I need to get rid of this warning... Or any ideas on how to use sleep with miliseconds. </p>
  
  <pre><code>#define _BSB_SOURCE
  #include &lt;pthread.h&gt;
  #include &lt;stdio.h&gt;
  #include &lt;stdlib.h&gt;
  #include &lt;stdbool.h&gt;
  #include &lt;unistd.h&gt;
  #include &lt;time.h&gt;
  
  int r = rand() % 1000 +1;
  usleep(r*1000);        
  pthread_mutex_lock (&amp;count_mutex);
  </code></pre>