How to implement inter-process locks/semaphores?

Question

linux

Which IPC to use to lock certain actions in a program running in different processes?
Target OS - Linux, preferably Linux + OS X.
Implementation language - Python, but cross-language locking is desirable, for example PHP + Python.
Google told me about semaphore.h/sem_open.
1. Is it a good choice?
2. A very cursory search showed me that there are no analogues in the languages ​​​​above. Am I wrong?
3. There is sem_get in php, but the first parameter in it is not a string, but a number. Apparently they are not that compatible.
4. Why is it so unpopular? Crutches are constantly used, from the most common - lock files.
5. What should I do if network work is needed? Probably, there is some server with similar functionality.

Answer 1

https://pypi.org/project/posix_ipc/

Answer 2

Traditionally, processes in lanes use pid files. Nothing more cross-language has yet been invented like. Further, stray ala memkesh, radish and others like them, which are not always sparkling.