title: A simple C++ function with different answers on different computers
body: <p>Consider the code below which is basically gamma function in C++:</p>
  
  <pre><code> double myGamma(double x){
   return gamma(x);
  }
  </code></pre>
  
  <p>When I run the code on Mac OS 10.7.5, it works perfectly fine. However, when I run it on a unix server, it returns strange result. Does anyone know what the issue is? Is gamma() function different under linux system?</p>
  
  <p>Thanks,</p>