482 lines
17 KiB
C++
482 lines
17 KiB
C++
//
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// posix/basic_stream_descriptor.hpp
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// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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//
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// Copyright (c) 2003-2021 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_POSIX_BASIC_STREAM_DESCRIPTOR_HPP
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#define ASIO_POSIX_BASIC_STREAM_DESCRIPTOR_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 "asio/posix/descriptor.hpp"
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#if defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR) \
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|| defined(GENERATING_DOCUMENTATION)
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#include "asio/detail/push_options.hpp"
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namespace asio {
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namespace posix {
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/// Provides stream-oriented descriptor functionality.
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/**
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* The posix::basic_stream_descriptor class template provides asynchronous and
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* blocking stream-oriented descriptor functionality.
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*
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* @par Thread Safety
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* @e Distinct @e objects: Safe.@n
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* @e Shared @e objects: Unsafe.
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*
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* Synchronous @c read_some and @c write_some operations are thread safe with
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* respect to each other, if the underlying operating system calls are also
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* thread safe. This means that it is permitted to perform concurrent calls to
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* these synchronous operations on a single descriptor object. Other synchronous
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* operations, such as @c close, are not thread safe.
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*
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* @par Concepts:
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* AsyncReadStream, AsyncWriteStream, Stream, SyncReadStream, SyncWriteStream.
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*/
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template <typename Executor = any_io_executor>
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class basic_stream_descriptor
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: public basic_descriptor<Executor>
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{
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public:
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/// The type of the executor associated with the object.
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typedef Executor executor_type;
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/// Rebinds the descriptor type to another executor.
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template <typename Executor1>
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struct rebind_executor
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{
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/// The descriptor type when rebound to the specified executor.
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typedef basic_stream_descriptor<Executor1> other;
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};
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/// The native representation of a descriptor.
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typedef typename basic_descriptor<Executor>::native_handle_type
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native_handle_type;
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/// Construct a stream descriptor without opening it.
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/**
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* This constructor creates a stream descriptor without opening it. The
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* descriptor needs to be opened and then connected or accepted before data
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* can be sent or received on it.
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*
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* @param ex The I/O executor that the descriptor will use, by default, to
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* dispatch handlers for any asynchronous operations performed on the
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* descriptor.
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*/
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explicit basic_stream_descriptor(const executor_type& ex)
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: basic_descriptor<Executor>(ex)
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{
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}
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/// Construct a stream descriptor without opening it.
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/**
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* This constructor creates a stream descriptor without opening it. The
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* descriptor needs to be opened and then connected or accepted before data
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* can be sent or received on it.
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*
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* @param context An execution context which provides the I/O executor that
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* the descriptor will use, by default, to dispatch handlers for any
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* asynchronous operations performed on the descriptor.
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*/
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template <typename ExecutionContext>
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explicit basic_stream_descriptor(ExecutionContext& context,
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typename constraint<
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is_convertible<ExecutionContext&, execution_context&>::value,
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defaulted_constraint
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>::type = defaulted_constraint())
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: basic_descriptor<Executor>(context)
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{
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}
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/// Construct a stream descriptor on an existing native descriptor.
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/**
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* This constructor creates a stream descriptor object to hold an existing
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* native descriptor.
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*
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* @param ex The I/O executor that the descriptor will use, by default, to
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* dispatch handlers for any asynchronous operations performed on the
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* descriptor.
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*
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* @param native_descriptor The new underlying descriptor implementation.
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*
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* @throws asio::system_error Thrown on failure.
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*/
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basic_stream_descriptor(const executor_type& ex,
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const native_handle_type& native_descriptor)
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: basic_descriptor<Executor>(ex, native_descriptor)
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{
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}
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/// Construct a stream descriptor on an existing native descriptor.
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/**
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* This constructor creates a stream descriptor object to hold an existing
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* native descriptor.
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*
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* @param context An execution context which provides the I/O executor that
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* the descriptor will use, by default, to dispatch handlers for any
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* asynchronous operations performed on the descriptor.
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*
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* @param native_descriptor The new underlying descriptor implementation.
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*
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* @throws asio::system_error Thrown on failure.
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*/
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template <typename ExecutionContext>
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basic_stream_descriptor(ExecutionContext& context,
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const native_handle_type& native_descriptor,
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typename constraint<
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is_convertible<ExecutionContext&, execution_context&>::value
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>::type = 0)
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: basic_descriptor<Executor>(context, native_descriptor)
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{
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}
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#if defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
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/// Move-construct a stream descriptor from another.
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/**
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* This constructor moves a stream descriptor from one object to another.
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*
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* @param other The other stream descriptor object from which the move
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* will occur.
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*
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* @note Following the move, the moved-from object is in the same state as if
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* constructed using the @c basic_stream_descriptor(const executor_type&)
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* constructor.
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*/
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basic_stream_descriptor(basic_stream_descriptor&& other) ASIO_NOEXCEPT
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: descriptor(std::move(other))
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{
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}
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/// Move-assign a stream descriptor from another.
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/**
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* This assignment operator moves a stream descriptor from one object to
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* another.
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*
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* @param other The other stream descriptor object from which the move
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* will occur.
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*
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* @note Following the move, the moved-from object is in the same state as if
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* constructed using the @c basic_stream_descriptor(const executor_type&)
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* constructor.
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*/
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basic_stream_descriptor& operator=(basic_stream_descriptor&& other)
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{
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descriptor::operator=(std::move(other));
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return *this;
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}
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#endif // defined(ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
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/// Write some data to the descriptor.
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/**
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* This function is used to write data to the stream descriptor. The function
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* call will block until one or more bytes of the data has been written
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* successfully, or until an error occurs.
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*
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* @param buffers One or more data buffers to be written to the descriptor.
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*
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* @returns The number of bytes written.
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*
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* @throws asio::system_error Thrown on failure. An error code of
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* asio::error::eof indicates that the connection was closed by the
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* peer.
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*
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* @note The write_some operation may not transmit all of the data to the
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* peer. Consider using the @ref write function if you need to ensure that
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* all data is written before the blocking operation completes.
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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
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* descriptor.write_some(asio::buffer(data, size));
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* @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 ConstBufferSequence>
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std::size_t write_some(const ConstBufferSequence& buffers)
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{
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asio::error_code ec;
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std::size_t s = this->impl_.get_service().write_some(
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this->impl_.get_implementation(), buffers, ec);
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asio::detail::throw_error(ec, "write_some");
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return s;
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}
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/// Write some data to the descriptor.
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/**
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* This function is used to write data to the stream descriptor. The function
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* call will block until one or more bytes of the data has been written
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* successfully, or until an error occurs.
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*
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* @param buffers One or more data buffers to be written to the descriptor.
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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. Returns 0 if an error occurred.
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*
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* @note The write_some operation may not transmit all of the data to the
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* peer. Consider using the @ref write function if you need to ensure that
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* all data is written before the blocking operation completes.
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*/
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template <typename ConstBufferSequence>
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std::size_t write_some(const ConstBufferSequence& buffers,
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asio::error_code& ec)
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{
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return this->impl_.get_service().write_some(
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this->impl_.get_implementation(), buffers, ec);
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}
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/// Start an asynchronous write.
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/**
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* This function is used to asynchronously write data to the stream
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* descriptor. The function call always returns immediately.
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*
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* @param buffers One or more data buffers to be written to the descriptor.
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* Although the buffers object may be copied as necessary, ownership of the
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* underlying memory blocks is retained by the caller, which must guarantee
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* that they remain valid until the handler is called.
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*
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* @param handler The handler to be called when the write operation completes.
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* Copies will be made of the handler as required. The function signature of
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* the handler must be:
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* @code void handler(
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* const asio::error_code& error, // Result of operation.
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* std::size_t bytes_transferred // Number of bytes written.
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* ); @endcode
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* Regardless of whether the asynchronous operation completes immediately or
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* not, the handler will not be invoked from within this function. On
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* immediate completion, invocation of the handler will be performed in a
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* manner equivalent to using asio::post().
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*
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* @note The write operation may not transmit all of the data to the peer.
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* Consider using the @ref async_write function if you need to ensure that all
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* data is written before the asynchronous operation completes.
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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
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* descriptor.async_write_some(asio::buffer(data, size), handler);
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* @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 ConstBufferSequence,
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ASIO_COMPLETION_TOKEN_FOR(void (asio::error_code,
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std::size_t)) WriteHandler
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ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)>
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ASIO_INITFN_AUTO_RESULT_TYPE(WriteHandler,
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void (asio::error_code, std::size_t))
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async_write_some(const ConstBufferSequence& buffers,
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ASIO_MOVE_ARG(WriteHandler) handler
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ASIO_DEFAULT_COMPLETION_TOKEN(executor_type))
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{
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return async_initiate<WriteHandler,
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void (asio::error_code, std::size_t)>(
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initiate_async_write_some(this), handler, buffers);
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}
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/// Read some data from the descriptor.
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/**
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* This function is used to read data from the stream descriptor. The function
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* call will block until one or more bytes of data has been read successfully,
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* or until an error occurs.
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*
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* @param buffers One or more buffers into which the data will be read.
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*
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* @returns The number of bytes read.
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*
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* @throws asio::system_error Thrown on failure. An error code of
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* asio::error::eof indicates that the connection was closed by the
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* peer.
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*
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* @note The read_some operation may not read all of the requested number of
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* bytes. Consider using the @ref read function if you need to ensure that
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* the requested amount of data is read before the blocking operation
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* completes.
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*
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* @par Example
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* To read into a single data buffer use the @ref buffer function as follows:
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* @code
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* descriptor.read_some(asio::buffer(data, size));
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* @endcode
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* See the @ref buffer documentation for information on reading into 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 MutableBufferSequence>
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std::size_t read_some(const MutableBufferSequence& buffers)
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{
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asio::error_code ec;
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std::size_t s = this->impl_.get_service().read_some(
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this->impl_.get_implementation(), buffers, ec);
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asio::detail::throw_error(ec, "read_some");
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return s;
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}
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/// Read some data from the descriptor.
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/**
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* This function is used to read data from the stream descriptor. The function
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* call will block until one or more bytes of data has been read successfully,
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* or until an error occurs.
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*
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* @param buffers One or more buffers into which the data will be read.
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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 read. Returns 0 if an error occurred.
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*
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* @note The read_some operation may not read all of the requested number of
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* bytes. Consider using the @ref read function if you need to ensure that
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* the requested amount of data is read before the blocking operation
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* completes.
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*/
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template <typename MutableBufferSequence>
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std::size_t read_some(const MutableBufferSequence& buffers,
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asio::error_code& ec)
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{
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return this->impl_.get_service().read_some(
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this->impl_.get_implementation(), buffers, ec);
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}
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/// Start an asynchronous read.
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/**
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* This function is used to asynchronously read data from the stream
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* descriptor. The function call always returns immediately.
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*
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* @param buffers One or more buffers into which the data will be read.
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* Although the buffers object may be copied as necessary, ownership of the
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* underlying memory blocks is retained by the caller, which must guarantee
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* that they remain valid until the handler is called.
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*
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* @param handler The handler to be called when the read operation completes.
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* Copies will be made of the handler as required. The function signature of
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* the handler must be:
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* @code void handler(
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* const asio::error_code& error, // Result of operation.
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* std::size_t bytes_transferred // Number of bytes read.
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* ); @endcode
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* Regardless of whether the asynchronous operation completes immediately or
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* not, the handler will not be invoked from within this function. On
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* immediate completion, invocation of the handler will be performed in a
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* manner equivalent to using asio::post().
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*
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* @note The read operation may not read all of the requested number of bytes.
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* Consider using the @ref async_read function if you need to ensure that the
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* requested amount of data is read before the asynchronous operation
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* completes.
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*
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* @par Example
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* To read into a single data buffer use the @ref buffer function as follows:
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* @code
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* descriptor.async_read_some(asio::buffer(data, size), handler);
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* @endcode
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* See the @ref buffer documentation for information on reading into 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 MutableBufferSequence,
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ASIO_COMPLETION_TOKEN_FOR(void (asio::error_code,
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std::size_t)) ReadHandler
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ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(executor_type)>
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ASIO_INITFN_AUTO_RESULT_TYPE(ReadHandler,
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void (asio::error_code, std::size_t))
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async_read_some(const MutableBufferSequence& buffers,
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ASIO_MOVE_ARG(ReadHandler) handler
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ASIO_DEFAULT_COMPLETION_TOKEN(executor_type))
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{
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return async_initiate<ReadHandler,
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void (asio::error_code, std::size_t)>(
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initiate_async_read_some(this), handler, buffers);
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}
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private:
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class initiate_async_write_some
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{
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public:
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typedef Executor executor_type;
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explicit initiate_async_write_some(basic_stream_descriptor* self)
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: self_(self)
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{
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}
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executor_type get_executor() const ASIO_NOEXCEPT
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{
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return self_->get_executor();
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}
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template <typename WriteHandler, typename ConstBufferSequence>
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void operator()(ASIO_MOVE_ARG(WriteHandler) handler,
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const ConstBufferSequence& buffers) const
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{
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// If you get an error on the following line it means that your handler
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// does not meet the documented type requirements for a WriteHandler.
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ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;
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detail::non_const_lvalue<WriteHandler> handler2(handler);
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self_->impl_.get_service().async_write_some(
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self_->impl_.get_implementation(), buffers,
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handler2.value, self_->impl_.get_executor());
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}
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private:
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basic_stream_descriptor* self_;
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};
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class initiate_async_read_some
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{
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public:
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typedef Executor executor_type;
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explicit initiate_async_read_some(basic_stream_descriptor* self)
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: self_(self)
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{
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}
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executor_type get_executor() const ASIO_NOEXCEPT
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{
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return self_->get_executor();
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}
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template <typename ReadHandler, typename MutableBufferSequence>
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void operator()(ASIO_MOVE_ARG(ReadHandler) handler,
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const MutableBufferSequence& buffers) const
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{
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// If you get an error on the following line it means that your handler
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// does not meet the documented type requirements for a ReadHandler.
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ASIO_READ_HANDLER_CHECK(ReadHandler, handler) type_check;
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detail::non_const_lvalue<ReadHandler> handler2(handler);
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self_->impl_.get_service().async_read_some(
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self_->impl_.get_implementation(), buffers,
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handler2.value, self_->impl_.get_executor());
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}
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private:
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basic_stream_descriptor* self_;
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};
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};
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} // namespace posix
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} // namespace asio
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#include "asio/detail/pop_options.hpp"
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#endif // defined(ASIO_HAS_POSIX_STREAM_DESCRIPTOR)
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// || defined(GENERATING_DOCUMENTATION)
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#endif // ASIO_POSIX_BASIC_STREAM_DESCRIPTOR_HPP
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