knnMatch() returning strange match counts and indices

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In the match object populated by knnMatch() (K=1, either unique or not) I get strange pattern of match counts for each entry returned - the counts order is typically [x, y, 7, 8, x, y, 7, 8, ...] (x/y typically 0 or 1 which make sense). Once in a while wild numbers (e.g. 8521267) are set there.

In addition, the indices of the first matches are also often wild numbers, built from 0xEEEEEEEE/0xABABABAB/0xCDCDCDCD, which seem to indicate they point to some wrong heap areas.

I include a snapshot of the compact returned values from VS 2012 and the test code I used, still before meaningful code has been run.

Hope someone can explain this, point to something wrong I did, or is that a real bug? Any workaround in this case?

I was also suspecting a possible incompatibility between STL versions between my build and the OpenCV library, but I didn't see such issues when searching.

This happens with 2.4.6

--- Returned values ---
-       matches { size=128 }    ::vector<std::vector<cv::DMatch,std::allocator<cv::DMatch> >,std::allocator<std::vector<cv::DMatch,std::allocator<cv::DMatch> > > >
        [size]  128 __int64
        [capacity]  128 __int64
+       [0] { size=1 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [1] { size=1 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [2] { size=7 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [3] { size=8 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [4] { size=1 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [5] { size=1 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [6] { size=7 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [7] { size=8 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [8] { size=1 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [9] { size=1 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [10]    { size=7 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [11]    { size=8 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [12]    { size=0 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [13]    { size=0 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [14]    { size=7 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [15]    { size=8 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [16]    { size=1 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [17]    { size=1 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [18]    { size=7 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [19]    { size=8 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [20]    { size=0 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [21]    { size=1 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [22]    { size=7 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [23]    { size=8521267 }    std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [24]    { size=0 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
+       [25]    { size=1 }  std::vector<cv::DMatch,std::allocator<cv::DMatch> >
...
 
--- Test Function (based on sample code) ---

#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include "opencv2 ...