title: C++ pattern for extra pass-by-reference arguments that aren't needed after the function call?
body: <p>Is there a preferred pattern for defining throwaway variables in C++ to pass to functions which take arguments by reference? One example of this is in using openCV's minmaxLoc function:</p>
  
  <pre><code>void minMaxLoc(const Mat&amp; src, double* minVal, double* maxVal=0, Point* minLoc=0, Point* maxLoc=0, const Mat&amp; mask=Mat())
  </code></pre>
  
  <p>The function changes the value of minVal, maxVal, minLoc, maxLoc to correspond to the min/max intensity values and locations.</p>
  
  <p>I could declare dummy variables for all of the parameters, but I really only need maxLoc. Is there a preferred C++ pattern such that I only declare maxLoc and don't clutter up my code with extra declarations of variables that I'm defining for the sake of calling minMaxLoc()?</p>