Question

我刚才注意到async_write_some中的async_send和boost::asio（第二次重载）函数完全相同：

async_write_some defenition：

...
template <typename ConstBufferSequence, typename WriteHandler>
  BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler,
      void (boost::system::error_code, std::size_t))
  async_write_some(const ConstBufferSequence& buffers,
      BOOST_ASIO_MOVE_ARG(WriteHandler) handler)
  {
    // If you get an error on the following line it means that your handler does
    // not meet the documented type requirements for a WriteHandler.
    BOOST_ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;

    return this->get_service().async_send(this->get_implementation(),
        buffers, 0, BOOST_ASIO_MOVE_CAST(WriteHandler)(handler));
  }
...

async_send定义：

...
template <typename ConstBufferSequence, typename WriteHandler>
  BOOST_ASIO_INITFN_RESULT_TYPE(WriteHandler,
      void (boost::system::error_code, std::size_t))
  async_send(const ConstBufferSequence& buffers,
      BOOST_ASIO_MOVE_ARG(WriteHandler) handler)
  {
    // If you get an error on the following line it means that your handler does
    // not meet the documented type requirements for a WriteHandler.
    BOOST_ASIO_WRITE_HANDLER_CHECK(WriteHandler, handler) type_check;

    return this->get_service().async_send(
        this->get_implementation(), buffers, 0,
        BOOST_ASIO_MOVE_CAST(WriteHandler)(handler));
  }
...

为什么boost::asio库中有两个相同的函数？有历史原因吗？

谢谢！

Answer 1

它们提供两种不同的抽象：

stream.async_write_some()允许一般性地写入异步流I / O对象。例如，此抽象允许更高级别的async_write()组合操作一般写入ip::tcp::socket，ssl:stream，serial_port等。async_write_some()成员函数是AsyncWriteStream类型要求的一部分。
socket.async_send()允许一个人一般地写入套接字而不考虑协议。例如，这种抽象允许一个人一般写入ip::tcp::socket，ip::udp::socket，local::*_protocol::socket和generic::*_protocol::socket。 socket.async_send()模型的存在与已建立的BSD套接字API紧密相关。

Boost :: asio async_write_some vs async_send

1 个答案: