opencv namedWindow leak ( c++ and opencv ) - c++

Question

Running valgrind, I get loads of memory leaks in opencv, especially with the function of namedWindow.
In the main, I have an image CSImg and PGImg:
std::string cs = "Computer Science Students";
std::string pg = "Politics and Government Students";
CSImg.displayImage(cs);
cv::destroyWindow(cs);
PGImg.displayImage(pg);
cv::destroyWindow(pg);
display image function is:
void ImageHandler::displayImage(std::string& windowname){
namedWindow(windowname);
imshow(windowname, m_image);
waitKey(7000);
}
Valgrind is giving me enormous memory leaks when I do displayImage.
For example:
==6561== 2,359,544 bytes in 1 blocks are possibly lost in loss record 3,421 of 3,421
==6561== at 0x4C2B3F8: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==6561== by 0x4F6C94C: cv::fastMalloc(unsigned long) (in /usr/lib/libopencv_core.so.2.3.1)
==6561== by 0x4F53650: cvCreateData (in /usr/lib/libopencv_core.so.2.3.1)
==6561== by 0x4F540F0: cvCreateMat (in /usr/lib/libopencv_core.so.2.3.1)
==6561== by 0x56435AF: cvImageWidgetSetImage(_CvImageWidget*, void const*) (in /usr/lib/libopencv_highgui.so.2.3.1)
==6561== by 0x5644C14: cvShowImage (in /usr/lib/libopencv_highgui.so.2.3.1)
==6561== by 0x5642AF7: cv::imshow(std::string const&, cv::_InputArray const&) (in /usr/lib/libopencv_highgui.so.2.3.1)
==6561== by 0x40CED7: ImageHandler::displayImage(std::string&) (imagehandler.cpp:33)
==6561== by 0x408CF5: main (randomU.cpp:601)
imagehandler.cpp, line 33 is:
imshow(windowname, m_image); //the full function is written above ^
randomU.cpp line 601 is:
CSImg.displayImage(cs);
Any help is appreciated.
Ask for any further info you need.

Answer 1

Sorry, the stark reality looks like OpenCV leaks. It leaks from the side of its Qt interface too due to self-references according to the Leaks Instrument (XCode tools).
Other proof that this is not just a false alarm: On my Mac, Opencv 2.4.3 continuously grows in the memory (according to Activity Monitor) when processing webcam input. (I am not using any pointers or data strorages so theoretically my OpenCV program should remain of constant size.)

Answer 2

Actually you don't need to call namedWindow anymore. You just call a "naked" cv::imshow(windowname,m_image). It works fine even if you overwrite.
REMARK:
waitKey has two usages:
1. to wait forever, then waitKey(0);
2. to wait for just a bit, possibly because you are displaying input from your webcam. Then do waitKey(30); (or less, depending on the fps of what you are playing. For movies, 30.)