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


Async handle type.

void (*uv_async_cb)(uv_async_t* handle)

Type definition for callback passed to uv_async_init().

Public members


See also

The uv_handle_t members also apply.


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.


Unlike other handle initialization functions, it immediately starts the handle.

int uv_async_send(uv_async_t* async)

Wakeup the event loop and call the async handle’s callback.


It’s safe to call this function from any thread. The callback will be called on the loop thread.


libuv will coalesce calls to uv_async_send(), that is, not every call to it will yield an execution of the callback. For example: if uv_async_send() is called 5 times in a row before the callback is called, the callback will only be called once. If uv_async_send() is called again after the callback was called, it will be called again.

See also

The uv_handle_t API functions also apply.