[/
 / 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)
 /]

[section:SeqPacketSocketService Sequenced packet socket service requirements]

A sequenced packet socket service must meet the requirements for a [link
asio.reference.SocketService socket service], as well as the additional
requirements listed below.

In the table below, `X` denotes a stream socket service class, `a` denotes a
value of type `X`, `b` denotes a value of type `X::implementation_type`, `ec`
denotes a value of type `error_code`, `f` denotes a value of type
`socket_base::message_flags`, `g` denotes an lvalue of type
`socket_base::message_flags`, `mb` denotes a value satisfying [link
asio.reference.MutableBufferSequence mutable buffer sequence] requirements,
`rh` denotes a value meeting [link asio.reference.ReadHandler `ReadHandler`]
requirements, `cb` denotes a value satisfying [link
asio.reference.ConstBufferSequence constant buffer sequence] requirements, and
`wh` denotes a value meeting [link asio.reference.WriteHandler `WriteHandler`]
requirements.

[table StreamSocketService requirements
  [[expression] [return type] [assertion/note\npre/post-condition]]
  [
    [`a.receive(b, mb, f, g, ec);`]
    [`size_t`]
    [
      pre: `a.is_open(b)`.\n
      \n
      Reads one or more bytes of data from a connected socket `b`.\n
      \n
      The mutable buffer sequence `mb` specifies memory where the data should
      be placed. The operation shall always fill a buffer in the sequence
      completely before proceeding to the next.\n
      \n
      If successful, sets `g` to the flags associated with the received data,
      and returns the number of bytes read. Otherwise, sets `g` to `0` and
      returns `0`.
    ]
  ]
  [
    [`a.async_receive(b, mb, f, g, rh);`]
    [`void`]
    [
      pre: `a.is_open(b)`.\n
      \n
      Initiates an asynchronous operation to read one or more bytes of data
      from a connected socket `b`. The operation is performed via the
      `io_service` object `a.get_io_service()` and behaves according to [link
      asio.reference.asynchronous_operations asynchronous operation]
      requirements.\n
      \n
      The mutable buffer sequence `mb` specifies memory where the data should
      be placed. The operation shall always fill a buffer in the sequence
      completely before proceeding to the next.\n
      \n
      The implementation shall maintain one or more copies of `mb` until such
      time as the read operation no longer requires access to the memory
      specified by the buffers in the sequence. The program must ensure the
      memory is valid until:\n
      \n
      [mdash] the last copy of `mb` is destroyed, or\n
      \n
      [mdash] the handler for the asynchronous operation is invoked,\n
      \n
      whichever comes first.\n
      \n
      If the operation completes successfully, sets `g` to the flags associated
      with the received data, then invokes the `ReadHandler` object `rh` with
      the number of bytes transferred. Otherwise, sets `g` to `0` and invokes
      `rh` with `0` bytes transferred.
    ]
  ]
  [
    [`a.send(b, cb, f, ec);`]
    [`size_t`]
    [
      pre: `a.is_open(b)`.\n
      \n
      Writes one or more bytes of data to a connected socket `b`.\n
      \n
      The constant buffer sequence `cb` specifies memory where the data to be
      written is located. The operation shall always write a buffer in the
      sequence completely before proceeding to the next.\n
      \n
      If successful, returns the number of bytes written. Otherwise returns `0`.
    ]
  ]
  [
    [`a.async_send(b, cb, f, wh);`]
    [`void`]
    [
      pre: `a.is_open(b)`.\n
      \n
      Initiates an asynchronous operation to write one or more bytes of data to
      a connected socket `b`. The operation is performed via the `io_service`
      object `a.get_io_service()` and behaves according to [link
      asio.reference.asynchronous_operations asynchronous operation]
      requirements.\n
      \n
      The constant buffer sequence `cb` specifies memory where the data to be
      written is located. The operation shall always write a buffer in the
      sequence completely before proceeding to the next.\n
      \n
      The implementation shall maintain one or more copies of `cb` until such
      time as the write operation no longer requires access to the memory
      specified by the buffers in the sequence. The program must ensure the
      memory is valid until:\n
      \n
      [mdash] the last copy of `cb` is destroyed, or\n
      \n
      [mdash] the handler for the asynchronous operation is invoked,\n
      \n
      whichever comes first.\n
      \n
      If the operation completes successfully, the `WriteHandler` object `wh`
      is invoked with the number of bytes transferred. Otherwise it is invoked
      with `0`.
    ]
  ]
]

[endsect]
