comparison DEPENDENCIES/generic/include/boost/asio/write_at.hpp @ 16:2665513ce2d3

Add boost headers

+//
+// write_at.hpp
+// ~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2013 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef BOOST_ASIO_WRITE_AT_HPP
+#define BOOST_ASIO_WRITE_AT_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include <boost/asio/detail/config.hpp>
+#include <cstddef>
+#include <boost/asio/async_result.hpp>
+#include <boost/asio/basic_streambuf_fwd.hpp>
+#include <boost/asio/detail/cstdint.hpp>
+#include <boost/asio/error.hpp>
+
+#include <boost/asio/detail/push_options.hpp>
+
+namespace boost {
+namespace asio {
+
+/**
+ * @defgroup write_at boost::asio::write_at
+ *
+ * @brief Write a certain amount of data at a specified offset before returning.
+ */
+/*@{*/
+
+/// 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
+ * 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 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
+ * 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 buffers One or more buffers containing the data to be written. The sum
+ * of the buffer sizes indicates the maximum number of bytes to write to the
+ * device.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws boost::system::system_error Thrown on failure.
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code boost::asio::write_at(d, 42, boost::asio::buffer(data, size)); @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.
+ *
+ * @note This overload is equivalent to calling:
+ * @code boost::asio::write_at(
+ *     d, offset, buffers,
+ *     boost::asio::transfer_all()); @endcode
+ */
+template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers);
+
+/// 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
+ * 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 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
+ * 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 buffers One or more buffers containing the data to be written. The sum
+ * of the buffer sizes indicates the maximum number of bytes to write to the
+ * device.
+ *
+ * @param ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code boost::asio::write_at(d, 42,
+ *     boost::asio::buffer(data, size), ec); @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.
+ *
+ * @note This overload is equivalent to calling:
+ * @code boost::asio::write_at(
+ *     d, offset, buffers,
+ *     boost::asio::transfer_all(), ec); @endcode
+ */
+template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers,
+    boost::system::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 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
+ * 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 buffers One or more buffers containing the data to be written. The sum
+ * of the buffer sizes indicates the maximum number of bytes to write to the
+ * device.
+ *
+ * @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 boost::system::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 boost::system::system_error Thrown on failure.
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code boost::asio::write_at(d, 42, boost::asio::buffer(data, size),
+ *     boost::asio::transfer_at_least(32)); @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.
+ */
+template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence,
+    typename CompletionCondition>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition);
+
+/// 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 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
+ * 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 buffers One or more buffers containing the data to be written. The sum
+ * of the buffer sizes indicates the maximum number of bytes to write to the
+ * device.
+ *
+ * @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 boost::system::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 ConstBufferSequence,
+    typename CompletionCondition>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition, boost::system::error_code& ec);
+
+#if !defined(BOOST_ASIO_NO_IOSTREAM)
+
+/// 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
+ * 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 An error occurred.
+ *
+ * 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.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @throws boost::system::system_error Thrown on failure.
+ *
+ * @note This overload is equivalent to calling:
+ * @code boost::asio::write_at(
+ *     d, 42, b,
+ *     boost::asio::transfer_all()); @endcode
+ */
+template <typename SyncRandomAccessWriteDevice, typename Allocator>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, basic_streambuf<Allocator>& b);
+
+/// 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
+ * 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 An error occurred.
+ *
+ * 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 ec Set to indicate what error occurred, if any.
+ *
+ * @returns The number of bytes transferred.
+ *
+ * @note This overload is equivalent to calling:
+ * @code boost::asio::write_at(
+ *     d, 42, b,
+ *     boost::asio::transfer_all(), ec); @endcode
+ */
+template <typename SyncRandomAccessWriteDevice, typename Allocator>
+std::size_t write_at(SyncRandomAccessWriteDevice& d,
+    uint64_t offset, basic_streambuf<Allocator>& b,
+    boost::system::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 boost::system::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 boost::system::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);
+
+/// 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 boost::system::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,
+    boost::system::error_code& ec);
+
+#endif // !defined(BOOST_ASIO_NO_IOSTREAM)
+
+/*@}*/
+/**
+ * @defgroup async_write_at boost::asio::async_write_at
+ *
+ * @brief Start an asynchronous operation to write a certain amount of data at
+ * the specified offset.
+ */
+/*@{*/
+
+/// 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. The function call
+ * 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 handler is called.
+ *
+ * @param handler 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:
+ * @code void handler(
+ *   // Result of operation.
+ *   const boost::system::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 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().
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code
+ * boost::asio::async_write_at(d, 42, boost::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.
+ */
+template <typename AsyncRandomAccessWriteDevice, typename ConstBufferSequence,
+    typename WriteHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (boost::system::error_code, std::size_t))
+async_write_at(AsyncRandomAccessWriteDevice& d, uint64_t offset,
+    const ConstBufferSequence& buffers,
+    BOOST_ASIO_MOVE_ARG(WriteHandler) handler);
+
+/// 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. The function call
+ * 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 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 boost::system::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 handler 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:
+ * @code void handler(
+ *   // Result of operation.
+ *   const boost::system::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 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().
+ *
+ * @par Example
+ * To write a single data buffer use the @ref buffer function as follows:
+ * @code boost::asio::async_write_at(d, 42,
+ *     boost::asio::buffer(data, size),
+ *     boost::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.
+ */
+template <typename AsyncRandomAccessWriteDevice, typename ConstBufferSequence,
+    typename CompletionCondition, typename WriteHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (boost::system::error_code, std::size_t))
+async_write_at(AsyncRandomAccessWriteDevice& d,
+    uint64_t offset, const ConstBufferSequence& buffers,
+    CompletionCondition completion_condition,
+    BOOST_ASIO_MOVE_ARG(WriteHandler) handler);
+
+#if !defined(BOOST_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. The function call
+ * 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 handler is called.
+ *
+ * @param handler 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:
+ * @code void handler(
+ *   // Result of operation.
+ *   const boost::system::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 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().
+ */
+template <typename AsyncRandomAccessWriteDevice, typename Allocator,
+    typename WriteHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (boost::system::error_code, std::size_t))
+async_write_at(AsyncRandomAccessWriteDevice& d, uint64_t offset,
+    basic_streambuf<Allocator>& b, BOOST_ASIO_MOVE_ARG(WriteHandler) handler);
+
+/// 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. The function call
+ * 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 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 boost::system::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 handler 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:
+ * @code void handler(
+ *   // Result of operation.
+ *   const boost::system::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 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().
+ */
+template <typename AsyncRandomAccessWriteDevice, typename Allocator,
+    typename CompletionCondition, typename WriteHandler>
+BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler,
+    void (boost::system::error_code, std::size_t))
+async_write_at(AsyncRandomAccessWriteDevice& d, uint64_t offset,
+    basic_streambuf<Allocator>& b, CompletionCondition completion_condition,
+    BOOST_ASIO_MOVE_ARG(WriteHandler) handler);
+
+#endif // !defined(BOOST_ASIO_NO_IOSTREAM)
+
+/*@}*/
+
+} // namespace asio
+} // namespace boost
+
+#include <boost/asio/detail/pop_options.hpp>
+
+#include <boost/asio/impl/write_at.hpp>
+
+#endif // BOOST_ASIO_WRITE_AT_HPP