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c++multithreadingatomic

std::atomic_flag initialization result

Is is really necessery to initialize std::atomic_flag in this way:

std::atomic_flag flag = ATOMIC_FLAG_INIT;

In my opinion it should have same result:

std::atomic_flag flag;
flag.clear();

I have read all about this class from cppreference, but I am still not sure.

Solution

  • According to ATOMIC_FLAG_INIT spec:

    This is the only way to initialize std::atomic_flag to a definite value: the value held after any other initialization is unspecified.