title: C: Undefined symbols for architecture x86_64
body: <p>I call the function <code>phtread_kill(gpsNavigationThread, 0)</code> and ge the following error</p>
  
  <blockquote>
    <p>Undefined symbols for architecture x86_64:</p>
  </blockquote>
  
  <pre><code>"_phtread_kill", referenced from:
    _startgpswatchdog in ccXXNhjy.o
  ld: symbol(s) not found for architecture x86_64
  </code></pre>
  
  <p>I <code>#include &lt;pthread.h&gt;</code> so am not sure what the issue is.</p>
  
  <p>I link as follows</p>
  
  <pre><code>gcc gps_nav.c dijk.c serial.c parser.c nav_corelogic.c -I/usr/include/libxml2 -lxml2 -lm -lpthread -o logic
  </code></pre>
  
  <p>I also #include signal.h but am not sure if there is a library for linking with it.</p>