ceph/src/boost/libs/asio/doc/overview/reactor.qbk

   1 [/
   2  / Copyright (c) 2003-2016 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   3  /
   4  / Distributed under the Boost Software License, Version 1.0. (See accompanying
   5  / file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6  /]
   7
   8 [section:reactor Reactor-Style Operations]
   9
  10 Sometimes a program must be integrated with a third-party library that wants to
  11 perform the I/O operations itself. To facilitate this, Boost.Asio includes a
  12 `null_buffers` type that can be used with both read and write operations. A
  13 `null_buffers` operation doesn't return until the I/O object is "ready" to
  14 perform the operation.
  15
  16 As an example, to perform a non-blocking read something like the
  17 following may be used:
  18
  19   ip::tcp::socket socket(my_io_service);
  20   ...
  21   socket.non_blocking(true);
  22   ...
  23   socket.async_read_some(null_buffers(), read_handler);
  24   ...
  25   void read_handler(boost::system::error_code ec)
  26   {
  27     if (!ec)
  28     {
  29       std::vector<char> buf(socket.available());
  30       socket.read_some(buffer(buf));
  31     }
  32   }
  33
  34 These operations are supported for sockets on all platforms, and for the POSIX
  35 stream-oriented descriptor classes.
  36
  37 [heading See Also]
  38
  39 [link boost_asio.reference.null_buffers null_buffers],
  40 [link boost_asio.reference.basic_socket.non_blocking basic_socket::non_blocking()],
  41 [link boost_asio.reference.basic_socket.native_non_blocking basic_socket::native_non_blocking()],
  42 [link boost_asio.examples.cpp03_examples.nonblocking nonblocking example].
  43
  44 [endsect]