<pre><code class="cpp">
vector < vector<Point> > contours;
contours.clear(); - ok
OutputArrayOfArrays &ref = contours;
ref.clear(); << start
</code></pre>

call stack:
<pre>
opencv_core249d.dll!cv::_InputArray::type(int i) Line 1194 + 0xd bytes C++
opencv_core249d.dll!cv::_InputArray::type(int i) Line 1194 + 0xf bytes C++
opencv_core249d.dll!cv::_InputArray::type(int i) Line 1194 + 0xf bytes C++
opencv_core249d.dll!cv::_OutputArray::clear() Line 1563 + 0xf bytes C++
> win32.exe!ContourDetect::getContours(cv::Mat & img) Line 94 + 0x15 bytes C++
</pre>

keep calling:

<pre><code class="cpp">
int k = kind();
</code></pre>

Visual Studio says that:
<pre>
kind = 0x01381c62 cv::_InputArray::type(int) ????? how
</pre>