You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
678 lines
27 KiB
678 lines
27 KiB
//
|
|
// write_at.hpp
|
|
// ~~~~~~~~~~~~
|
|
//
|
|
// Copyright (c) 2003-2016 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 ASIO_WRITE_AT_HPP
|
|
#define ASIO_WRITE_AT_HPP
|
|
|
|
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
|
|
# pragma once
|
|
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
|
|
|
|
#include "asio/detail/config.hpp"
|
|
#include <cstddef>
|
|
#include "asio/async_result.hpp"
|
|
#include "asio/detail/cstdint.hpp"
|
|
#include "asio/error.hpp"
|
|
|
|
#if !defined(ASIO_NO_EXTENSIONS)
|
|
# include "asio/basic_streambuf_fwd.hpp"
|
|
#endif // !defined(ASIO_NO_EXTENSIONS)
|
|
|
|
#include "asio/detail/push_options.hpp"
|
|
|
|
namespace asio {
|
|
|
|
/**
|
|
* @defgroup write_at 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 asio::system_error Thrown on failure.
|
|
*
|
|
* @par Example
|
|
* To write a single data buffer use the @ref buffer function as follows:
|
|
* @code asio::write_at(d, 42, 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 asio::write_at(
|
|
* d, offset, buffers,
|
|
* 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 asio::write_at(d, 42,
|
|
* 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 asio::write_at(
|
|
* d, offset, buffers,
|
|
* asio::transfer_all(), ec); @endcode
|
|
*/
|
|
template <typename SyncRandomAccessWriteDevice, typename ConstBufferSequence>
|
|
std::size_t write_at(SyncRandomAccessWriteDevice& d,
|
|
uint64_t offset, const ConstBufferSequence& buffers,
|
|
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 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 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.
|
|
*
|
|
* @par Example
|
|
* To write a single data buffer use the @ref buffer function as follows:
|
|
* @code asio::write_at(d, 42, asio::buffer(data, size),
|
|
* 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 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 ConstBufferSequence,
|
|
typename CompletionCondition>
|
|
std::size_t write_at(SyncRandomAccessWriteDevice& d,
|
|
uint64_t offset, const ConstBufferSequence& buffers,
|
|
CompletionCondition completion_condition, asio::error_code& ec);
|
|
|
|
#if !defined(ASIO_NO_EXTENSIONS)
|
|
#if !defined(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 asio::system_error Thrown on failure.
|
|
*
|
|
* @note This overload is equivalent to calling:
|
|
* @code asio::write_at(
|
|
* d, 42, b,
|
|
* 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 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);
|
|
|
|
/// 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);
|
|
|
|
#endif // !defined(ASIO_NO_IOSTREAM)
|
|
#endif // !defined(ASIO_NO_EXTENSIONS)
|
|
|
|
/*@}*/
|
|
/**
|
|
* @defgroup async_write_at 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 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 handler will not be invoked from within this function. Invocation of
|
|
* the handler will be performed in a manner equivalent to using
|
|
* asio::io_context::post().
|
|
*
|
|
* @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.
|
|
*/
|
|
template <typename AsyncRandomAccessWriteDevice, typename ConstBufferSequence,
|
|
typename WriteHandler>
|
|
ASIO_INITFN_RESULT_TYPE(WriteHandler,
|
|
void (asio::error_code, std::size_t))
|
|
async_write_at(AsyncRandomAccessWriteDevice& d, uint64_t offset,
|
|
const ConstBufferSequence& buffers,
|
|
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 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 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 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 handler will not be invoked from within this function. Invocation of
|
|
* the handler will be performed in a manner equivalent to using
|
|
* asio::io_context::post().
|
|
*
|
|
* @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.
|
|
*/
|
|
template <typename AsyncRandomAccessWriteDevice, typename ConstBufferSequence,
|
|
typename CompletionCondition, typename WriteHandler>
|
|
ASIO_INITFN_RESULT_TYPE(WriteHandler,
|
|
void (asio::error_code, std::size_t))
|
|
async_write_at(AsyncRandomAccessWriteDevice& d,
|
|
uint64_t offset, const ConstBufferSequence& buffers,
|
|
CompletionCondition completion_condition,
|
|
ASIO_MOVE_ARG(WriteHandler) handler);
|
|
|
|
#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. 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 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 handler will not be invoked from within this function. Invocation of
|
|
* the handler will be performed in a manner equivalent to using
|
|
* asio::io_context::post().
|
|
*/
|
|
template <typename AsyncRandomAccessWriteDevice, typename Allocator,
|
|
typename WriteHandler>
|
|
ASIO_INITFN_RESULT_TYPE(WriteHandler,
|
|
void (asio::error_code, std::size_t))
|
|
async_write_at(AsyncRandomAccessWriteDevice& d, uint64_t offset,
|
|
basic_streambuf<Allocator>& b, 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 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 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 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 handler will not be invoked from within this function. Invocation of
|
|
* the handler will be performed in a manner equivalent to using
|
|
* asio::io_context::post().
|
|
*/
|
|
template <typename AsyncRandomAccessWriteDevice, typename Allocator,
|
|
typename CompletionCondition, typename WriteHandler>
|
|
ASIO_INITFN_RESULT_TYPE(WriteHandler,
|
|
void (asio::error_code, std::size_t))
|
|
async_write_at(AsyncRandomAccessWriteDevice& d, uint64_t offset,
|
|
basic_streambuf<Allocator>& b, CompletionCondition completion_condition,
|
|
ASIO_MOVE_ARG(WriteHandler) handler);
|
|
|
|
#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
|