title: OpenMP - index variable in OpenMP 'for' statement must have signed integral type
body: <p>I'm new to OpenMP. I'm trying to use multiple cores for a for loop but I get this compiling error:</p>
  
  <p>"error C3016: 'x' : index variable in OpenMP 'for' statement must have signed integral type".</p>
  
  <p>I know OpenMP 2.0, which is standard with Microsoft Visual Studio 2010 ( what I'm using ), does not support unsigned data types for some reason but I don't believe I have any unsigned data types being used in this loop.</p>
  
  <p>Here is how my code looks like:</p>
  
  <p>Variable Declerations:</p>
  
  <pre><code>struct Vertex
  {
      float x, y;
  };
  
  FractalGenerator::Vertex FractalGenerator::_fracStart;
  FractalGenerator::Vertex FractalGenerator::_fracEnd;
  float FractalGenerator::_pointPrecision = 0.008f;
  float FractalGenerator::_scaleFactor = 1;
  </code></pre>
  
  <p>For Loop:</p>
  
  <pre><code>float _fracStep =  _pointPrecision / _scaleFactor;
  
  #pragma omp parallel for
  for (float x = _fracStart.x; x &lt; _fracEnd.x; x += _fracStep)
  {
      for (float y = _fracStart.y; y &lt; _fracEnd.y; y += _fracStep)
      {
  </code></pre>