...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Perform the WebSocket closing handshake asynchronously and close the underlying stream.
template< class CloseHandler = net::default_completion_token_t<executor_type>> DEDUCED async_close( close_reason const& cr, CloseHandler&& handler = net::default_completion_token_t< executor_type >{});
This function sends a close
frame to begin the WebSocket closing handshake and waits for a
corresponding close frame in response. Once received, it calls async_teardown
to gracefully shut
down the underlying stream asynchronously.
After beginning the closing handshake, the program should not write further
message data, pings, or pongs. However, it can still read incoming message
data. A read returning error::closed
indicates a successful
connection closure.
This call always returns immediately. The asynchronous operation will continue until one of the following conditions is true:
async_teardown
finishes.
If a timeout occurs, close_socket
will be called to
close the underlying stream.
The algorithm, known as a composed asynchronous operation,
is implemented in terms of calls to the next layer's async_write_some
function. No other operations except for message reading operations should
be initiated on the stream after a close operation is started.
Name |
Description |
---|---|
|
The reason for the close. If the close reason specifies a close
code other than |
|
The completion handler to invoke when the operation completes. The implementation takes ownership of the handler by performing a decay-copy. The equivalent function signature of the handler must be: void handler( error_code const & ec // Result of operation );
If the handler has an associated immediate executor, an immediate
completion will be dispatched to it. Otherwise, the handler will
not be invoked from within this function. Invocation of the handler
will be performed by dispatching to the immediate executor. If
no immediate executor is specified, this is equivalent to using
|
This asynchronous operation supports cancellation for the following net::cancellation_type values:
net::cancellation_type::terminal
net::cancellation_type::total
total
cancellation succeeds
if the operation is suspended due to ongoing control operations such as
a ping/pong.
terminal
cancellation succeeds
when supported by the underlying stream.
terminal
cancellation may
close the underlying socket.