1 2.. _async: 3 4:c:type:`uv_async_t` --- Async handle 5===================================== 6 7Async handles allow the user to "wakeup" the event loop and get a callback 8called from another thread. 9 10 11Data types 12---------- 13 14.. c:type:: uv_async_t 15 16 Async handle type. 17 18.. c:type:: void (*uv_async_cb)(uv_async_t* handle) 19 20 Type definition for callback passed to :c:func:`uv_async_init`. 21 22 23Public members 24^^^^^^^^^^^^^^ 25 26N/A 27 28.. seealso:: The :c:type:`uv_handle_t` members also apply. 29 30 31API 32--- 33 34.. c:function:: int uv_async_init(uv_loop_t* loop, uv_async_t* async, uv_async_cb async_cb) 35 36 Initialize the handle. A NULL callback is allowed. 37 38 :returns: 0 on success, or an error code < 0 on failure. 39 40 .. note:: 41 Unlike other handle initialization functions, it immediately starts the handle. 42 43.. c:function:: int uv_async_send(uv_async_t* async) 44 45 Wake up the event loop and call the async handle's callback. 46 47 :returns: 0 on success, or an error code < 0 on failure. 48 49 .. note:: 50 It's safe to call this function from any thread. The callback will be called on the 51 loop thread. 52 53 .. note:: 54 :c:func:`uv_async_send` is `async-signal-safe <https://man7.org/linux/man-pages/man7/signal-safety.7.html>`_. 55 It's safe to call this function from a signal handler. 56 57 .. warning:: 58 libuv will coalesce calls to :c:func:`uv_async_send`, that is, not every call to it will 59 yield an execution of the callback. For example: if :c:func:`uv_async_send` is called 5 60 times in a row before the callback is called, the callback will only be called once. If 61 :c:func:`uv_async_send` is called again after the callback was called, it will be called 62 again. 63 64.. seealso:: 65 The :c:type:`uv_handle_t` API functions also apply. 66
