title: argc atoi argv, Opencv, C++
body: <p>can you explain what does it mean?</p>
  
  <pre><code> argc &gt;= 3 ? atoi(argv[2]) : 40;
  </code></pre>
  
  <p>And second question : does exist libarries of function - parameters which is necessary, structure something like this</p>
  
  <pre><code> CVAPI(void)  cvAddS( const CvArr* src, CvScalar value, CvArr* dst,
                   const CvArr* mask CV_DEFAULT(NULL));
  </code></pre>