Quick Q: why there is no data-race in the following case?

Quick A: No write is triggered so no data race occurs.

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why there is no data-race in the following case?

Data races are not static properties of your code. They are properties of the actual state of the program at execution time. So while that program could be in a state where the code would produce a data race, that's not the question.

The question is, given the state of the system, will the code cause a data race? And since the program is in a state such that neither thread will write to either variable, then the code will not cause a data race.

Data races aren't about what your code might do. It's about what they will do. Just as a function that takes a pointer isn't undefined behavior just because it uses the pointer without checking for NULL. It is only UB if someone passes a pointer that really is NULL.

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