Adds an I/O watch as with add_watch, but using the given async_context.
| async_context |
the MainContext to dispatch the I/O watch in, or |
| chan |
the IOChannel to watch |
| condition |
the condition to watch for |
| function |
the callback to invoke when |
| data |
user data to pass to |
|
a SocketSource, which can be removed from |