c++ - 在构造不同的元素时， 'std::allocator<T>::construct' 是线程安全的吗？

Question

c++标准是否保证用std::allocator构造不同的元素是线程安全的？例如:

// main thread
std::allocator<T> alloc;
auto *p = alloc.allocate(2);

// thread1
alloc.construct(p);

// thread2
alloc.construct(p + 1)

另外，std::allocator::destroy 对于不同的元素是线程安全的吗？

谢谢!

Answer 1

20.7.9.1 allocator members [allocator.members]

1 Except for the destructor, member functions of the default allocator shall not introduce data races (1.10) as a result of concurrent calls to those member functions from different threads. Calls to these functions that allocate or deallocate a particular unit of storage shall occur in a single total order, and each such deallocation call shall happen before the next allocation (if any) in this order.

是的，并发调用 construct和 destroy在 std::allocator<T>保证是线程安全的。