opencv - CascadeClassifier::detectMultiScale doesn't work with C++ -

i'm using opencv , cascadeclassifier::detectmultiscale facial detection. problem seems cause memory corruption on output vector<rect>. vector correctly filled rects, causes crash when vector deallocated.

this occurs when compiling debug build. error message debug assertion failed, makes me wonder if there problem occurs in release build, , assert isn't checked.

could bug opencv? or i'm doing wrong how handle vectors?

the following code snippet shows example code reproduce bug:

#include <opencv2/opencv.hpp> using namespace cv;  int main(array<system::string ^> ^args) {     videocapture video(0);     mat frame;     cascadeclassifier classifier("haarcascade_frontalface_default.xml");      while (waitkey(1000 / 30) != 'q')     {         video >> frame;          vector<rect> faces;         classifier.detectmultiscale(frame, faces);         (int = 0; < faces.size(); i++)             rectangle(frame, faces[i], scalar(255, 255, 255));          imshow("camera", frame);     } // <<< crash occurs here when faces vector released } 

i following error message:

debug assertion failed!

program: myprogram.exe file: minkernel\crts\ucrt\src\appcrt\heap\debug_heap.cpp line: 892

expression: is_block_type_valid(header->_block_use)

i had same issue. solved passing dereferenced global pointer function.

i.e.

    std::vector<cv::rect>* faces = nullptr;      void init()     {         faces = new std::vector<cv::rect>; //never call delete whatever     }      void findsomefaces()     {         cascade->detectmultiscale(image_source, *faces);     }