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Start an asynchronous write at the specified offset.
template<
typename ConstBufferSequence,
typename WriteHandler = DEFAULT>
DEDUCED async_write_some_at(
uint64_t offset,
const ConstBufferSequence & buffers,
WriteHandler && handler = DEFAULT);
This function is used to asynchronously write data to the random-access handle. The function call always returns immediately.
The offset at which the data will be written.
One or more data buffers to be written to the handle. 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 asio::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 post.
The write operation may not transmit all of the data to the peer. Consider
using the async_write_at
function if you need to ensure that all data is written before the asynchronous
operation completes.
To write a single data buffer use the buffer
function as follows:
handle.async_write_some_at(42, asio::buffer(data, size), handler);
See the buffer
documentation for information on writing multiple buffers in one go, and
how to use it with arrays, boost::array or std::vector.
This asynchronous operation supports cancellation for the following cancellation_type
values:
cancellation_type::terminal
cancellation_type::partial
cancellation_type::total