template< typename ConstBufferSequence, typename WriteHandler = DEFAULT> DEDUCED async_write_some( const ConstBufferSequence & buffers, WriteHandler && handler = DEFAULT);
This function is used to asynchronously write data to the stream file. The function call always returns immediately.
One or more data buffers to be written to the file. Although the buffers object may be copied as necessary, ownership of the underlying memory blocks is retained by the caller, which must guarantee that they remain valid until the handler is called.
The handler to be called when the write operation completes. Copies will be made of the handler as required. The function signature of the handler must be:
void handler( const boost::system::error_code& error, // Result of operation. std::size_t bytes_transferred // Number of bytes written. );
Regardless of whether the asynchronous operation completes immediately
or not, the handler will not be invoked from within this function.
On immediate completion, invocation of the handler will be performed
in a manner equivalent to using
The write operation may not transmit all of the data to the peer. Consider
function if you need to ensure that all data is written before the asynchronous
To write a single data buffer use the
function as follows:
file.async_write_some(boost::asio::buffer(data, size), handler);
documentation for information on writing multiple buffers in one go, and
how to use it with arrays, boost::array or std::vector.
On POSIX or Windows operating systems, this asynchronous operation supports
cancellation for the following