What are flocks in this context? Surely not a number of sheep...
https://man.openbsd.org/flock.2
https://man7.org/linux/man-pages/man2/flock.2.html
File locks.
https://man.openbsd.org/flock.2
https://man7.org/linux/man-pages/man2/flock.2.html
File locks.