Why do I need to acquire a lock to modify a shared “atomic” variable before notifying condition_variable

Question

Accoding to cppreference.com:

The thread that intends to modify the variable has to

1. acquire a std::mutex (typically via std::lock_

Answer 1

Found a very good explanation about this issue in another thread. Take a loot at

Questions where asked below about race conditions.

If the data being communicated is atomic, can't we do without the mutex on the "send" side?

at the end.