What's the correct way to delete all elements by HASH_ITER thead-safe ?

[GFHuang]

AcquireLock();

HASH_ITER(...) {
    HASH_DEL(...)
}

ReleaseLock();

or

HASH_ITER(...) {
    AcquireLock();

    HASH_DEL(...)

    ReleaseLock();
}

[GFHuang]

？