mutex

mutex is a mutex which supports asynchronous acquisition. When the mutex is contended, the operation asynchronously blocks until the current holder releases it.

Prototype

struct mutex {
	sender async_lock(); // (1)

	bool try_lock(); // (2)

	void unlock(); // (3)
};

1. Asynchronously acquire the mutex.
2. Synchronously try to acquire the mutex.
3. Release the mutex.

Return values

1. This method returns a sender of unspecified type. The sender does not return any value, and completes once the mutex is acquired.
2. This method returns true if the mutex was successfully acquired, false otherwise.
3. This method doesn't return any value.

Examples

async::mutex mtx;
async::queue<int, frg::stl_allocator> q;

auto coro = [] (int i, auto &mtx, auto &q) -> async::detached {
	std::cout << i << ": taking" << std::endl;
	co_await mtx.async_lock();
	std::cout << i << ": " << mtx.try_lock() << std::endl;
	co_await q.async_get();
	std::cout << i << ": releasing" << std::endl;
	mtx.unlock();
};

coro(1, mtx, q);
coro(2, mtx, q);

q.put(1);
q.put(2);

Output:

1: taking
1: 0
2: taking
1: releasing
2: 0
2: releasing