.. _async: :c:type:`uv_async_t` --- Async handle ===================================== Async handles allow the user to "wakeup" the event loop and get a callback called from another thread. Data types ---------- .. c:type:: uv_async_t Async handle type. .. c:type:: void (*uv_async_cb)(uv_async_t* handle) Type definition for callback passed to :c:func:`uv_async_init`. Public members ^^^^^^^^^^^^^^ N/A .. seealso:: The :c:type:`uv_handle_t` members also apply. API --- .. c:function:: int uv_async_init(uv_loop_t* loop, uv_async_t* async, uv_async_cb async_cb) Initialize the handle. A NULL callback is allowed. :returns: 0 on success, or an error code < 0 on failure. .. note:: Unlike other handle initialization functions, it immediately starts the handle. .. c:function:: int uv_async_send(uv_async_t* async) Wake up the event loop and call the async handle's callback. :returns: 0 on success, or an error code < 0 on failure. .. note:: It's safe to call this function from any thread. The callback will be called on the loop thread. .. note:: :c:func:`uv_async_send` is `async-signal-safe <http://man7.org/linux/man-pages/man7/signal-safety.7.html>`_. It's safe to call this function from a signal handler. .. warning:: libuv will coalesce calls to :c:func:`uv_async_send`, that is, not every call to it will yield an execution of the callback. For example: if :c:func:`uv_async_send` is called 5 times in a row before the callback is called, the callback will only be called once. If :c:func:`uv_async_send` is called again after the callback was called, it will be called again. .. seealso:: The :c:type:`uv_handle_t` API functions also apply.