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include/asio/write_at.hpp
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include/asio/write_at.hpp
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//
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// write_at.hpp
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// ~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2025 Christopher M. Kohlhoff (chris at kohlhoff dot com)
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#ifndef ASIO_WRITE_AT_HPP
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#define ASIO_WRITE_AT_HPP
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#if defined(_MSC_VER) && (_MSC_VER >= 1200)
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# pragma once
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#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
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#include "asio/detail/config.hpp"
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#include <cstddef>
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#include "asio/async_result.hpp"
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#include "asio/completion_condition.hpp"
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#include "asio/detail/cstdint.hpp"
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#include "asio/error.hpp"
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#if !defined(ASIO_NO_EXTENSIONS)
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# include "asio/basic_streambuf_fwd.hpp"
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#endif // !defined(ASIO_NO_EXTENSIONS)
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#include "asio/detail/push_options.hpp"
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namespace asio {
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namespace detail {
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template <typename> class initiate_async_write_at;
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#if !defined(ASIO_NO_IOSTREAM)
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template <typename> class initiate_async_write_at_streambuf;
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#endif // !defined(ASIO_NO_IOSTREAM)
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} // namespace detail
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/**
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* @defgroup write_at asio::write_at
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*
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* @brief The @c write_at function is a composed operation that writes a
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* certain amount of data at a specified offset before returning.
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*/
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/*@{*/
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/// Write all of the supplied data at the specified offset before returning.
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/**
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* This function is used to write a certain number of bytes of data to a random
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* access device at a specified offset. The call will block until one of the
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* following conditions is true:
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*
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* @li All of the data in the supplied buffers has been written. That is, the
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* bytes transferred is equal to the sum of the buffer sizes.
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*
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* @li An error occurred.
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*
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* This operation is implemented in terms of zero or more calls to the device's
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* write_some_at function.
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*
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* @param d The device to which the data is to be written. The type must support
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* the SyncRandomAccessWriteDevice concept.
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*
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* @param offset The offset at which the data will be written.
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*
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* @param buffers One or more buffers containing the data to be written. The sum
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* of the buffer sizes indicates the maximum number of bytes to write to the
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* device.
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*
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* @returns The number of bytes transferred.
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*
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* @throws asio::system_error Thrown on failure.
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*
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* @par Example
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* To write a single data buffer use the @ref buffer function as follows:
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* @code asio::write_at(d, 42, asio::buffer(data, size)); @endcode
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* See the @ref buffer documentation for information on writing multiple
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* buffers in one go, and how to use it with arrays, boost::array or
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* std::vector.
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*
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* @note This overload is equivalent to calling:
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* @code asio::write_at(
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* d, offset, buffers,
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* asio::transfer_all()); @endcode
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*/
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template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence>
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std::size_t write_at(SyncRandomAccessWriteDevice& d,
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uint64_t offset, const ConstBufferSequence& buffers);
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/// Write all of the supplied data at the specified offset before returning.
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/**
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* This function is used to write a certain number of bytes of data to a random
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* access device at a specified offset. The call will block until one of the
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* following conditions is true:
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*
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* @li All of the data in the supplied buffers has been written. That is, the
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* bytes transferred is equal to the sum of the buffer sizes.
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*
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* @li An error occurred.
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*
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* This operation is implemented in terms of zero or more calls to the device's
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* write_some_at function.
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*
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* @param d The device to which the data is to be written. The type must support
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* the SyncRandomAccessWriteDevice concept.
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*
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* @param offset The offset at which the data will be written.
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*
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* @param buffers One or more buffers containing the data to be written. The sum
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* of the buffer sizes indicates the maximum number of bytes to write to the
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* device.
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*
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* @param ec Set to indicate what error occurred, if any.
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*
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* @returns The number of bytes transferred.
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*
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* @par Example
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* To write a single data buffer use the @ref buffer function as follows:
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* @code asio::write_at(d, 42,
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* asio::buffer(data, size), ec); @endcode
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* See the @ref buffer documentation for information on writing multiple
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* buffers in one go, and how to use it with arrays, boost::array or
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* std::vector.
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*
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* @note This overload is equivalent to calling:
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* @code asio::write_at(
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* d, offset, buffers,
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* asio::transfer_all(), ec); @endcode
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*/
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template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence>
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std::size_t write_at(SyncRandomAccessWriteDevice& d,
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uint64_t offset, const ConstBufferSequence& buffers,
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asio::error_code& ec);
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/// Write a certain amount of data at a specified offset before returning.
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/**
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* This function is used to write a certain number of bytes of data to a random
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* access device at a specified offset. The call will block until one of the
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* following conditions is true:
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*
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* @li All of the data in the supplied buffers has been written. That is, the
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* bytes transferred is equal to the sum of the buffer sizes.
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*
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* @li The completion_condition function object returns 0.
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*
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* This operation is implemented in terms of zero or more calls to the device's
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* write_some_at function.
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*
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* @param d The device to which the data is to be written. The type must support
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* the SyncRandomAccessWriteDevice concept.
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*
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* @param offset The offset at which the data will be written.
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*
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* @param buffers One or more buffers containing the data to be written. The sum
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* of the buffer sizes indicates the maximum number of bytes to write to the
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* device.
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*
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* @param completion_condition The function object to be called to determine
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* whether the write operation is complete. The signature of the function object
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* must be:
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* @code std::size_t completion_condition(
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* // Result of latest write_some_at operation.
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* const asio::error_code& error,
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*
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* // Number of bytes transferred so far.
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* std::size_t bytes_transferred
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* ); @endcode
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* A return value of 0 indicates that the write operation is complete. A
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* non-zero return value indicates the maximum number of bytes to be written on
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* the next call to the device's write_some_at function.
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*
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* @returns The number of bytes transferred.
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*
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* @throws asio::system_error Thrown on failure.
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*
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* @par Example
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* To write a single data buffer use the @ref buffer function as follows:
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* @code asio::write_at(d, 42, asio::buffer(data, size),
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* asio::transfer_at_least(32)); @endcode
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||||
* See the @ref buffer documentation for information on writing multiple
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* buffers in one go, and how to use it with arrays, boost::array or
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* std::vector.
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*/
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template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence,
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typename CompletionCondition>
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std::size_t write_at(SyncRandomAccessWriteDevice& d,
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uint64_t offset, const ConstBufferSequence& buffers,
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CompletionCondition completion_condition,
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constraint_t<
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is_completion_condition<CompletionCondition>::value
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||||
> = 0);
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/// Write a certain amount of data at a specified offset before returning.
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/**
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* This function is used to write a certain number of bytes of data to a random
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* access device at a specified offset. The call will block until one of the
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* following conditions is true:
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||||
*
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||||
* @li All of the data in the supplied buffers has been written. That is, the
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||||
* bytes transferred is equal to the sum of the buffer sizes.
|
||||
*
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||||
* @li The completion_condition function object returns 0.
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||||
*
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||||
* This operation is implemented in terms of zero or more calls to the device's
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||||
* write_some_at function.
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||||
*
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* @param d The device to which the data is to be written. The type must support
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* the SyncRandomAccessWriteDevice concept.
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*
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* @param offset The offset at which the data will be written.
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*
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* @param buffers One or more buffers containing the data to be written. The sum
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* of the buffer sizes indicates the maximum number of bytes to write to the
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* device.
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*
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* @param completion_condition The function object to be called to determine
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* whether the write operation is complete. The signature of the function object
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* must be:
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* @code std::size_t completion_condition(
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* // Result of latest write_some_at operation.
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* const asio::error_code& error,
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*
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* // Number of bytes transferred so far.
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* std::size_t bytes_transferred
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* ); @endcode
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* A return value of 0 indicates that the write operation is complete. A
|
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* non-zero return value indicates the maximum number of bytes to be written on
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* the next call to the device's write_some_at function.
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||||
*
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* @param ec Set to indicate what error occurred, if any.
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*
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* @returns The number of bytes written. If an error occurs, returns the total
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* number of bytes successfully transferred prior to the error.
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*/
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template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence,
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typename CompletionCondition>
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std::size_t write_at(SyncRandomAccessWriteDevice& d,
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uint64_t offset, const ConstBufferSequence& buffers,
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CompletionCondition completion_condition, asio::error_code& ec,
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constraint_t<
|
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is_completion_condition<CompletionCondition>::value
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||||
> = 0);
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|
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#if !defined(ASIO_NO_EXTENSIONS)
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#if !defined(ASIO_NO_IOSTREAM)
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/// Write all of the supplied data at the specified offset before returning.
|
||||
/**
|
||||
* This function is used to write a certain number of bytes of data to a random
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* access device at a specified offset. The call will block until one of the
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* following conditions is true:
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*
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* @li All of the data in the supplied basic_streambuf has been written.
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*
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* @li An error occurred.
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*
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||||
* This operation is implemented in terms of zero or more calls to the device's
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* write_some_at function.
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*
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* @param d The device to which the data is to be written. The type must support
|
||||
* the SyncRandomAccessWriteDevice concept.
|
||||
*
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* @param offset The offset at which the data will be written.
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*
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* @param b The basic_streambuf object from which data will be written.
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*
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* @returns The number of bytes transferred.
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*
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* @throws asio::system_error Thrown on failure.
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||||
*
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* @note This overload is equivalent to calling:
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* @code asio::write_at(
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* d, 42, b,
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* asio::transfer_all()); @endcode
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*/
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template <typename SyncRandomAccessWriteDevice, typename Allocator>
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std::size_t write_at(SyncRandomAccessWriteDevice& d,
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uint64_t offset, basic_streambuf<Allocator>& b);
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/// Write all of the supplied data at the specified offset before returning.
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/**
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* This function is used to write a certain number of bytes of data to a random
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* access device at a specified offset. The call will block until one of the
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* following conditions is true:
|
||||
*
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* @li All of the data in the supplied basic_streambuf has been written.
|
||||
*
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* @li An error occurred.
|
||||
*
|
||||
* This operation is implemented in terms of zero or more calls to the device's
|
||||
* write_some_at function.
|
||||
*
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||||
* @param d The device to which the data is to be written. The type must support
|
||||
* the SyncRandomAccessWriteDevice concept.
|
||||
*
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* @param offset The offset at which the data will be written.
|
||||
*
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* @param b The basic_streambuf object from which data will be written.
|
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*
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* @param ec Set to indicate what error occurred, if any.
|
||||
*
|
||||
* @returns The number of bytes transferred.
|
||||
*
|
||||
* @note This overload is equivalent to calling:
|
||||
* @code asio::write_at(
|
||||
* d, 42, b,
|
||||
* asio::transfer_all(), ec); @endcode
|
||||
*/
|
||||
template <typename SyncRandomAccessWriteDevice, typename Allocator>
|
||||
std::size_t write_at(SyncRandomAccessWriteDevice& d,
|
||||
uint64_t offset, basic_streambuf<Allocator>& b,
|
||||
asio::error_code& ec);
|
||||
|
||||
/// Write a certain amount of data at a specified offset before returning.
|
||||
/**
|
||||
* This function is used to write a certain number of bytes of data to a random
|
||||
* access device at a specified offset. The call will block until one of the
|
||||
* following conditions is true:
|
||||
*
|
||||
* @li All of the data in the supplied basic_streambuf has been written.
|
||||
*
|
||||
* @li The completion_condition function object returns 0.
|
||||
*
|
||||
* This operation is implemented in terms of zero or more calls to the device's
|
||||
* write_some_at function.
|
||||
*
|
||||
* @param d The device to which the data is to be written. The type must support
|
||||
* the SyncRandomAccessWriteDevice concept.
|
||||
*
|
||||
* @param offset The offset at which the data will be written.
|
||||
*
|
||||
* @param b The basic_streambuf object from which data will be written.
|
||||
*
|
||||
* @param completion_condition The function object to be called to determine
|
||||
* whether the write operation is complete. The signature of the function object
|
||||
* must be:
|
||||
* @code std::size_t completion_condition(
|
||||
* // Result of latest write_some_at operation.
|
||||
* const asio::error_code& error,
|
||||
*
|
||||
* // Number of bytes transferred so far.
|
||||
* std::size_t bytes_transferred
|
||||
* ); @endcode
|
||||
* A return value of 0 indicates that the write operation is complete. A
|
||||
* non-zero return value indicates the maximum number of bytes to be written on
|
||||
* the next call to the device's write_some_at function.
|
||||
*
|
||||
* @returns The number of bytes transferred.
|
||||
*
|
||||
* @throws asio::system_error Thrown on failure.
|
||||
*/
|
||||
template <typename SyncRandomAccessWriteDevice, typename Allocator,
|
||||
typename CompletionCondition>
|
||||
std::size_t write_at(SyncRandomAccessWriteDevice& d, uint64_t offset,
|
||||
basic_streambuf<Allocator>& b, CompletionCondition completion_condition,
|
||||
constraint_t<
|
||||
is_completion_condition<CompletionCondition>::value
|
||||
> = 0);
|
||||
|
||||
/// Write a certain amount of data at a specified offset before returning.
|
||||
/**
|
||||
* This function is used to write a certain number of bytes of data to a random
|
||||
* access device at a specified offset. The call will block until one of the
|
||||
* following conditions is true:
|
||||
*
|
||||
* @li All of the data in the supplied basic_streambuf has been written.
|
||||
*
|
||||
* @li The completion_condition function object returns 0.
|
||||
*
|
||||
* This operation is implemented in terms of zero or more calls to the device's
|
||||
* write_some_at function.
|
||||
*
|
||||
* @param d The device to which the data is to be written. The type must support
|
||||
* the SyncRandomAccessWriteDevice concept.
|
||||
*
|
||||
* @param offset The offset at which the data will be written.
|
||||
*
|
||||
* @param b The basic_streambuf object from which data will be written.
|
||||
*
|
||||
* @param completion_condition The function object to be called to determine
|
||||
* whether the write operation is complete. The signature of the function object
|
||||
* must be:
|
||||
* @code std::size_t completion_condition(
|
||||
* // Result of latest write_some_at operation.
|
||||
* const asio::error_code& error,
|
||||
*
|
||||
* // Number of bytes transferred so far.
|
||||
* std::size_t bytes_transferred
|
||||
* ); @endcode
|
||||
* A return value of 0 indicates that the write operation is complete. A
|
||||
* non-zero return value indicates the maximum number of bytes to be written on
|
||||
* the next call to the device's write_some_at function.
|
||||
*
|
||||
* @param ec Set to indicate what error occurred, if any.
|
||||
*
|
||||
* @returns The number of bytes written. If an error occurs, returns the total
|
||||
* number of bytes successfully transferred prior to the error.
|
||||
*/
|
||||
template <typename SyncRandomAccessWriteDevice, typename Allocator,
|
||||
typename CompletionCondition>
|
||||
std::size_t write_at(SyncRandomAccessWriteDevice& d,
|
||||
uint64_t offset, basic_streambuf<Allocator>& b,
|
||||
CompletionCondition completion_condition, asio::error_code& ec,
|
||||
constraint_t<
|
||||
is_completion_condition<CompletionCondition>::value
|
||||
> = 0);
|
||||
|
||||
#endif // !defined(ASIO_NO_IOSTREAM)
|
||||
#endif // !defined(ASIO_NO_EXTENSIONS)
|
||||
|
||||
/*@}*/
|
||||
/**
|
||||
* @defgroup async_write_at asio::async_write_at
|
||||
*
|
||||
* @brief The @c async_write_at function is a composed asynchronous operation
|
||||
* that writes a certain amount of data at the specified offset before
|
||||
* completion.
|
||||
*/
|
||||
/*@{*/
|
||||
|
||||
/// Start an asynchronous operation to write all of the supplied data at the
|
||||
/// specified offset.
|
||||
/**
|
||||
* This function is used to asynchronously write a certain number of bytes of
|
||||
* data to a random access device at a specified offset. It is an initiating
|
||||
* function for an @ref asynchronous_operation, and always returns immediately.
|
||||
* The asynchronous operation will continue until one of the following
|
||||
* conditions is true:
|
||||
*
|
||||
* @li All of the data in the supplied buffers has been written. That is, the
|
||||
* bytes transferred is equal to the sum of the buffer sizes.
|
||||
*
|
||||
* @li An error occurred.
|
||||
*
|
||||
* This operation is implemented in terms of zero or more calls to the device's
|
||||
* async_write_some_at function, and is known as a <em>composed operation</em>.
|
||||
* The program must ensure that the device performs no <em>overlapping</em>
|
||||
* write operations (such as async_write_at, the device's async_write_some_at
|
||||
* function, or any other composed operations that perform writes) until this
|
||||
* operation completes. Operations are overlapping if the regions defined by
|
||||
* their offsets, and the numbers of bytes to write, intersect.
|
||||
*
|
||||
* @param d The device to which the data is to be written. The type must support
|
||||
* the AsyncRandomAccessWriteDevice concept.
|
||||
*
|
||||
* @param offset The offset at which the data will be written.
|
||||
*
|
||||
* @param buffers One or more buffers containing the data to be written.
|
||||
* 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 completion handler is called.
|
||||
*
|
||||
* @param token The @ref completion_token that will be used to produce a
|
||||
* completion handler, which will be called when the write completes.
|
||||
* Potential completion tokens include @ref use_future, @ref use_awaitable,
|
||||
* @ref yield_context, or a function object with the correct completion
|
||||
* signature. The function signature of the completion handler must be:
|
||||
* @code void handler(
|
||||
* // Result of operation.
|
||||
* const asio::error_code& error,
|
||||
*
|
||||
* // Number of bytes written from the buffers. If an error
|
||||
* // occurred, this will be less than the sum of the buffer sizes.
|
||||
* std::size_t bytes_transferred
|
||||
* ); @endcode
|
||||
* Regardless of whether the asynchronous operation completes immediately or
|
||||
* not, the completion 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 asio::async_immediate().
|
||||
*
|
||||
* @par Completion Signature
|
||||
* @code void(asio::error_code, std::size_t) @endcode
|
||||
*
|
||||
* @par Example
|
||||
* To write a single data buffer use the @ref buffer function as follows:
|
||||
* @code
|
||||
* asio::async_write_at(d, 42, asio::buffer(data, size), handler);
|
||||
* @endcode
|
||||
* See the @ref buffer documentation for information on writing multiple
|
||||
* buffers in one go, and how to use it with arrays, boost::array or
|
||||
* std::vector.
|
||||
*
|
||||
* @par Per-Operation Cancellation
|
||||
* This asynchronous operation supports cancellation for the following
|
||||
* asio::cancellation_type values:
|
||||
*
|
||||
* @li @c cancellation_type::terminal
|
||||
*
|
||||
* @li @c cancellation_type::partial
|
||||
*
|
||||
* if they are also supported by the @c AsyncRandomAccessWriteDevice type's
|
||||
* async_write_some_at operation.
|
||||
*/
|
||||
template <typename AsyncRandomAccessWriteDevice, typename ConstBufferSequence,
|
||||
ASIO_COMPLETION_TOKEN_FOR(void (asio::error_code,
|
||||
std::size_t)) WriteToken = default_completion_token_t<
|
||||
typename AsyncRandomAccessWriteDevice::executor_type>>
|
||||
inline auto async_write_at(AsyncRandomAccessWriteDevice& d,
|
||||
uint64_t offset, const ConstBufferSequence& buffers,
|
||||
WriteToken&& token = default_completion_token_t<
|
||||
typename AsyncRandomAccessWriteDevice::executor_type>(),
|
||||
constraint_t<
|
||||
!is_completion_condition<WriteToken>::value
|
||||
> = 0)
|
||||
-> decltype(
|
||||
async_initiate<WriteToken,
|
||||
void (asio::error_code, std::size_t)>(
|
||||
declval<detail::initiate_async_write_at<
|
||||
AsyncRandomAccessWriteDevice>>(),
|
||||
token, offset, buffers, transfer_all()))
|
||||
{
|
||||
return async_initiate<WriteToken,
|
||||
void (asio::error_code, std::size_t)>(
|
||||
detail::initiate_async_write_at<AsyncRandomAccessWriteDevice>(d),
|
||||
token, offset, buffers, transfer_all());
|
||||
}
|
||||
|
||||
/// Start an asynchronous operation to write a certain amount of data at the
|
||||
/// specified offset.
|
||||
/**
|
||||
* This function is used to asynchronously write a certain number of bytes of
|
||||
* data to a random access device at a specified offset. It is an initiating
|
||||
* function for an @ref asynchronous_operation, and always returns immediately.
|
||||
* The asynchronous operation will continue until one of the following
|
||||
* conditions is true:
|
||||
*
|
||||
* @li All of the data in the supplied buffers has been written. That is, the
|
||||
* bytes transferred is equal to the sum of the buffer sizes.
|
||||
*
|
||||
* @li The completion_condition function object returns 0.
|
||||
*
|
||||
* This operation is implemented in terms of zero or more calls to the device's
|
||||
* async_write_some_at function, and is known as a <em>composed operation</em>.
|
||||
* The program must ensure that the device performs no <em>overlapping</em>
|
||||
* write operations (such as async_write_at, the device's async_write_some_at
|
||||
* function, or any other composed operations that perform writes) until this
|
||||
* operation completes. Operations are overlapping if the regions defined by
|
||||
* their offsets, and the numbers of bytes to write, intersect.
|
||||
*
|
||||
* @param d The device to which the data is to be written. The type must support
|
||||
* the AsyncRandomAccessWriteDevice concept.
|
||||
*
|
||||
* @param offset The offset at which the data will be written.
|
||||
*
|
||||
* @param buffers One or more buffers containing the data to be written.
|
||||
* 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 completion handler is called.
|
||||
*
|
||||
* @param completion_condition The function object to be called to determine
|
||||
* whether the write operation is complete. The signature of the function object
|
||||
* must be:
|
||||
* @code std::size_t completion_condition(
|
||||
* // Result of latest async_write_some_at operation.
|
||||
* const asio::error_code& error,
|
||||
*
|
||||
* // Number of bytes transferred so far.
|
||||
* std::size_t bytes_transferred
|
||||
* ); @endcode
|
||||
* A return value of 0 indicates that the write operation is complete. A
|
||||
* non-zero return value indicates the maximum number of bytes to be written on
|
||||
* the next call to the device's async_write_some_at function.
|
||||
*
|
||||
* @param token The @ref completion_token that will be used to produce a
|
||||
* completion handler, which will be called when the write completes.
|
||||
* Potential completion tokens include @ref use_future, @ref use_awaitable,
|
||||
* @ref yield_context, or a function object with the correct completion
|
||||
* signature. The function signature of the completion handler must be:
|
||||
* @code void handler(
|
||||
* // Result of operation.
|
||||
* const asio::error_code& error,
|
||||
*
|
||||
* // Number of bytes written from the buffers. If an error
|
||||
* // occurred, this will be less than the sum of the buffer sizes.
|
||||
* std::size_t bytes_transferred
|
||||
* ); @endcode
|
||||
* Regardless of whether the asynchronous operation completes immediately or
|
||||
* not, the completion 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 asio::async_immediate().
|
||||
*
|
||||
* @par Completion Signature
|
||||
* @code void(asio::error_code, std::size_t) @endcode
|
||||
*
|
||||
* @par Example
|
||||
* To write a single data buffer use the @ref buffer function as follows:
|
||||
* @code asio::async_write_at(d, 42,
|
||||
* asio::buffer(data, size),
|
||||
* asio::transfer_at_least(32),
|
||||
* handler); @endcode
|
||||
* See the @ref buffer documentation for information on writing multiple
|
||||
* buffers in one go, and how to use it with arrays, boost::array or
|
||||
* std::vector.
|
||||
*
|
||||
* @par Per-Operation Cancellation
|
||||
* This asynchronous operation supports cancellation for the following
|
||||
* asio::cancellation_type values:
|
||||
*
|
||||
* @li @c cancellation_type::terminal
|
||||
*
|
||||
* @li @c cancellation_type::partial
|
||||
*
|
||||
* if they are also supported by the @c AsyncRandomAccessWriteDevice type's
|
||||
* async_write_some_at operation.
|
||||
*/
|
||||
template <typename AsyncRandomAccessWriteDevice,
|
||||
typename ConstBufferSequence, typename CompletionCondition,
|
||||
ASIO_COMPLETION_TOKEN_FOR(void (asio::error_code,
|
||||
std::size_t)) WriteToken = default_completion_token_t<
|
||||
typename AsyncRandomAccessWriteDevice::executor_type>>
|
||||
inline auto async_write_at(AsyncRandomAccessWriteDevice& d,
|
||||
uint64_t offset, const ConstBufferSequence& buffers,
|
||||
CompletionCondition completion_condition,
|
||||
WriteToken&& token = default_completion_token_t<
|
||||
typename AsyncRandomAccessWriteDevice::executor_type>(),
|
||||
constraint_t<
|
||||
is_completion_condition<CompletionCondition>::value
|
||||
> = 0)
|
||||
-> decltype(
|
||||
async_initiate<WriteToken,
|
||||
void (asio::error_code, std::size_t)>(
|
||||
declval<detail::initiate_async_write_at<
|
||||
AsyncRandomAccessWriteDevice>>(),
|
||||
token, offset, buffers,
|
||||
static_cast<CompletionCondition&&>(completion_condition)))
|
||||
{
|
||||
return async_initiate<WriteToken,
|
||||
void (asio::error_code, std::size_t)>(
|
||||
detail::initiate_async_write_at<AsyncRandomAccessWriteDevice>(d),
|
||||
token, offset, buffers,
|
||||
static_cast<CompletionCondition&&>(completion_condition));
|
||||
}
|
||||
|
||||
#if !defined(ASIO_NO_EXTENSIONS)
|
||||
#if !defined(ASIO_NO_IOSTREAM)
|
||||
|
||||
/// Start an asynchronous operation to write all of the supplied data at the
|
||||
/// specified offset.
|
||||
/**
|
||||
* This function is used to asynchronously write a certain number of bytes of
|
||||
* data to a random access device at a specified offset. It is an initiating
|
||||
* function for an @ref asynchronous_operation, and always returns immediately.
|
||||
* The asynchronous operation will continue until one of the following
|
||||
* conditions is true:
|
||||
*
|
||||
* @li All of the data in the supplied basic_streambuf has been written.
|
||||
*
|
||||
* @li An error occurred.
|
||||
*
|
||||
* This operation is implemented in terms of zero or more calls to the device's
|
||||
* async_write_some_at function, and is known as a <em>composed operation</em>.
|
||||
* The program must ensure that the device performs no <em>overlapping</em>
|
||||
* write operations (such as async_write_at, the device's async_write_some_at
|
||||
* function, or any other composed operations that perform writes) until this
|
||||
* operation completes. Operations are overlapping if the regions defined by
|
||||
* their offsets, and the numbers of bytes to write, intersect.
|
||||
*
|
||||
* @param d The device to which the data is to be written. The type must support
|
||||
* the AsyncRandomAccessWriteDevice concept.
|
||||
*
|
||||
* @param offset The offset at which the data will be written.
|
||||
*
|
||||
* @param b A basic_streambuf object from which data will be written. Ownership
|
||||
* of the streambuf is retained by the caller, which must guarantee that it
|
||||
* remains valid until the completion handler is called.
|
||||
*
|
||||
* @param token The @ref completion_token that will be used to produce a
|
||||
* completion handler, which will be called when the write completes.
|
||||
* Potential completion tokens include @ref use_future, @ref use_awaitable,
|
||||
* @ref yield_context, or a function object with the correct completion
|
||||
* signature. The function signature of the completion handler must be:
|
||||
* @code void handler(
|
||||
* // Result of operation.
|
||||
* const asio::error_code& error,
|
||||
*
|
||||
* // Number of bytes written from the buffers. If an error
|
||||
* // occurred, this will be less than the sum of the buffer sizes.
|
||||
* std::size_t bytes_transferred
|
||||
* ); @endcode
|
||||
* Regardless of whether the asynchronous operation completes immediately or
|
||||
* not, the completion 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 asio::async_immediate().
|
||||
*
|
||||
* @par Completion Signature
|
||||
* @code void(asio::error_code, std::size_t) @endcode
|
||||
*
|
||||
* @par Per-Operation Cancellation
|
||||
* This asynchronous operation supports cancellation for the following
|
||||
* asio::cancellation_type values:
|
||||
*
|
||||
* @li @c cancellation_type::terminal
|
||||
*
|
||||
* @li @c cancellation_type::partial
|
||||
*
|
||||
* if they are also supported by the @c AsyncRandomAccessWriteDevice type's
|
||||
* async_write_some_at operation.
|
||||
*/
|
||||
template <typename AsyncRandomAccessWriteDevice, typename Allocator,
|
||||
ASIO_COMPLETION_TOKEN_FOR(void (asio::error_code,
|
||||
std::size_t)) WriteToken = default_completion_token_t<
|
||||
typename AsyncRandomAccessWriteDevice::executor_type>>
|
||||
inline auto async_write_at(AsyncRandomAccessWriteDevice& d,
|
||||
uint64_t offset, basic_streambuf<Allocator>& b,
|
||||
WriteToken&& token = default_completion_token_t<
|
||||
typename AsyncRandomAccessWriteDevice::executor_type>(),
|
||||
constraint_t<
|
||||
!is_completion_condition<WriteToken>::value
|
||||
> = 0)
|
||||
-> decltype(
|
||||
async_initiate<WriteToken,
|
||||
void (asio::error_code, std::size_t)>(
|
||||
declval<detail::initiate_async_write_at_streambuf<
|
||||
AsyncRandomAccessWriteDevice>>(),
|
||||
token, offset, &b, transfer_all()))
|
||||
{
|
||||
return async_initiate<WriteToken,
|
||||
void (asio::error_code, std::size_t)>(
|
||||
detail::initiate_async_write_at_streambuf<
|
||||
AsyncRandomAccessWriteDevice>(d),
|
||||
token, offset, &b, transfer_all());
|
||||
}
|
||||
|
||||
/// Start an asynchronous operation to write a certain amount of data at the
|
||||
/// specified offset.
|
||||
/**
|
||||
* This function is used to asynchronously write a certain number of bytes of
|
||||
* data to a random access device at a specified offset. It is an initiating
|
||||
* function for an @ref asynchronous_operation, and always returns immediately.
|
||||
* The asynchronous operation will continue until one of the following
|
||||
* conditions is true:
|
||||
*
|
||||
* @li All of the data in the supplied basic_streambuf has been written.
|
||||
*
|
||||
* @li The completion_condition function object returns 0.
|
||||
*
|
||||
* This operation is implemented in terms of zero or more calls to the device's
|
||||
* async_write_some_at function, and is known as a <em>composed operation</em>.
|
||||
* The program must ensure that the device performs no <em>overlapping</em>
|
||||
* write operations (such as async_write_at, the device's async_write_some_at
|
||||
* function, or any other composed operations that perform writes) until this
|
||||
* operation completes. Operations are overlapping if the regions defined by
|
||||
* their offsets, and the numbers of bytes to write, intersect.
|
||||
*
|
||||
* @param d The device to which the data is to be written. The type must support
|
||||
* the AsyncRandomAccessWriteDevice concept.
|
||||
*
|
||||
* @param offset The offset at which the data will be written.
|
||||
*
|
||||
* @param b A basic_streambuf object from which data will be written. Ownership
|
||||
* of the streambuf is retained by the caller, which must guarantee that it
|
||||
* remains valid until the completion handler is called.
|
||||
*
|
||||
* @param completion_condition The function object to be called to determine
|
||||
* whether the write operation is complete. The signature of the function object
|
||||
* must be:
|
||||
* @code std::size_t completion_condition(
|
||||
* // Result of latest async_write_some_at operation.
|
||||
* const asio::error_code& error,
|
||||
*
|
||||
* // Number of bytes transferred so far.
|
||||
* std::size_t bytes_transferred
|
||||
* ); @endcode
|
||||
* A return value of 0 indicates that the write operation is complete. A
|
||||
* non-zero return value indicates the maximum number of bytes to be written on
|
||||
* the next call to the device's async_write_some_at function.
|
||||
*
|
||||
* @param token The @ref completion_token that will be used to produce a
|
||||
* completion handler, which will be called when the write completes.
|
||||
* Potential completion tokens include @ref use_future, @ref use_awaitable,
|
||||
* @ref yield_context, or a function object with the correct completion
|
||||
* signature. The function signature of the completion handler must be:
|
||||
* @code void handler(
|
||||
* // Result of operation.
|
||||
* const asio::error_code& error,
|
||||
*
|
||||
* // Number of bytes written from the buffers. If an error
|
||||
* // occurred, this will be less than the sum of the buffer sizes.
|
||||
* std::size_t bytes_transferred
|
||||
* ); @endcode
|
||||
* Regardless of whether the asynchronous operation completes immediately or
|
||||
* not, the completion 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 asio::async_immediate().
|
||||
*
|
||||
* @par Completion Signature
|
||||
* @code void(asio::error_code, std::size_t) @endcode
|
||||
*
|
||||
* @par Per-Operation Cancellation
|
||||
* This asynchronous operation supports cancellation for the following
|
||||
* asio::cancellation_type values:
|
||||
*
|
||||
* @li @c cancellation_type::terminal
|
||||
*
|
||||
* @li @c cancellation_type::partial
|
||||
*
|
||||
* if they are also supported by the @c AsyncRandomAccessWriteDevice type's
|
||||
* async_write_some_at operation.
|
||||
*/
|
||||
template <typename AsyncRandomAccessWriteDevice,
|
||||
typename Allocator, typename CompletionCondition,
|
||||
ASIO_COMPLETION_TOKEN_FOR(void (asio::error_code,
|
||||
std::size_t)) WriteToken = default_completion_token_t<
|
||||
typename AsyncRandomAccessWriteDevice::executor_type>>
|
||||
inline auto async_write_at(AsyncRandomAccessWriteDevice& d, uint64_t offset,
|
||||
basic_streambuf<Allocator>& b, CompletionCondition completion_condition,
|
||||
WriteToken&& token = default_completion_token_t<
|
||||
typename AsyncRandomAccessWriteDevice::executor_type>(),
|
||||
constraint_t<
|
||||
is_completion_condition<CompletionCondition>::value
|
||||
> = 0)
|
||||
-> decltype(
|
||||
async_initiate<WriteToken,
|
||||
void (asio::error_code, std::size_t)>(
|
||||
declval<detail::initiate_async_write_at_streambuf<
|
||||
AsyncRandomAccessWriteDevice>>(),
|
||||
token, offset, &b,
|
||||
static_cast<CompletionCondition&&>(completion_condition)))
|
||||
{
|
||||
return async_initiate<WriteToken,
|
||||
void (asio::error_code, std::size_t)>(
|
||||
detail::initiate_async_write_at_streambuf<
|
||||
AsyncRandomAccessWriteDevice>(d),
|
||||
token, offset, &b,
|
||||
static_cast<CompletionCondition&&>(completion_condition));
|
||||
}
|
||||
|
||||
#endif // !defined(ASIO_NO_IOSTREAM)
|
||||
#endif // !defined(ASIO_NO_EXTENSIONS)
|
||||
|
||||
/*@}*/
|
||||
|
||||
} // namespace asio
|
||||
|
||||
#include "asio/detail/pop_options.hpp"
|
||||
|
||||
#include "asio/impl/write_at.hpp"
|
||||
|
||||
#endif // ASIO_WRITE_AT_HPP
|
||||
Reference in New Issue
Block a user