At ov_core/src/track/TrackKLT.cpp:532, you call:

Grider_FAST::perform_griding(img1pyr.at(0), pts1_ext, num_features, num_featsneeded_1, grid_x, grid_y, threshold, true)

where num_features is an int.

But Grider_FAST::perform_griding is defined at ov_core/src/track/Grider_FAST.h:L94 as:

void perform_griding(const cv::Mat&, std::vector<cv::KeyPoint>&, bool, int, int, int, int, bool)

num_features is implicitly coerced into a boolean; the one which determines if griding is performed with multiple threads. Is this a mistake or is it intentional?