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websocket::stream::async_pong

Start an asynchronous operation to send a WebSocket pong frame.

template<
    class WriteHandler>
void-or-deduced
async_pong(
    ping_data const& payload,
    WriteHandler&& handler);

This function is used to asynchronously send a pong frame to the stream. The function call always returns immediately. The asynchronous operation will continue until one of the following is true:

This operation is implemented in terms of one or more calls to the next layer's async_write_some functions, and is known as a composed operation. The program must ensure that the stream performs no other writes until this operation completes.

The WebSocket protocol allows pong frames to be sent from either end at any time. It is not necessary to first receive a ping in order to send a pong. The remote peer may use the receipt of a pong frame as an indication that the connection is not dead.

Parameters

payload

The payload of the pong message, which may be empty.

handler

The handler to be called when the read operation completes. Copies will be made of the handler as required. The function signature of the handler must be:

void handler(
    error_code const& error     // Result of operation
);

Regardless of whether the asynchronous operation completes immediately or not, the handler will not be invoked from within this function. Invocation of the handler will be performed in a manner equivalent to using boost::asio::io_service::post.


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