What is the checkerboard corner detection algorithm based on?

I read from http://stackoverflow.com/questions/27256994/what-is-the-best-calibration-method that Matlab camera calibration app currently provides the best checkerboard corner detection algorithm, however in http://www.mathworks.com/help/vision/ref/detectcheckerboardpoints.html I couldn't find what method or what paper it is based on. My goal is to find/implement a C++ based implementation because my code base is in C++. Can someone let me know?