tildefriends/deps/libuv/docs/src/async.rst

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.. _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 <https://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.