title: How do I build OpenCV with TBB?
body: <p>I'm trying and failing to make <code>opencv_traincascade</code> use multiple threads. The only documentation I can find says to &quot;build OpenCV with TBB&quot;. I'm not sure if I'm failing to successfully build OpenCV with TBB, or whether there's some flag I need to set for <code>opencv_traincascade</code>.</p>
  <p>I've downloaded the OpenCV version 2.3.1 windows superpack and <code>tbb40_20111003oss_win.zip</code>, which I extracted to <code>C:\tbb40_20111003oss</code>. I then generated VC8 <code>.sln</code> and <code>.proj</code> files using CMake, setting</p>
  <blockquote>
  <p><code>WITH_TBB: ON </code></p>
  <p><code>TBB_INCLUDE_DIR:PATH=C:\tbb40_20111003oss\include</code></p>
  <p><code>TBB_LIB_DIR:PATH=C:/tbb40_20111003oss/lib/intel64/vc8</code></p>
  </blockquote>
  <p>OpenCV then builds without errors, but when I run <code>opencv_traincascade</code> it's singlethreaded. Does anyone know what I'm doing wrong?</p>