的boost :: ASIO async_read_some async_read_until编译器警告

Question

我使用下面的方法：

boost::asio::streambuf io_bufstream; 

boost::asio::async_read_until(socket_, io_bufstream, "</message>", 
    strand_.wrap(
    boost::bind(&Connection::handleRead, shared_from_this(), 
    boost::asio::placeholders::error, 
    boost::asio::placeholders::bytes_transferred)));//warning: line 36 


boost::array<char, 8192> buffer_  
socket_.async_read_some(boost::asio::buffer(buffer_), 
    strand_.wrap(
    boost::bind(&Connection::handleRead, shared_from_this(), 
    boost::asio::placeholders::error, 
    boost::asio::placeholders::bytes_transferred))); // warning 

我得到以下警告：

C:\dev\sapphire\boost_1_46_1\boost/asio/detail/reactive_socket_recv_op.hpp(58) : warning C4800: 'int' : forcing value to bool 'true' or 'false' (performance warning) 

下面是完整的输出，以及：

C:\dev\sapphire\boost_1_46_1\boost/asio/detail/reactive_socket_recv_op.hpp(58) : warning C4800: 'int' : forcing value to bool 'true' or 'false' (performance warning) 
     C:\dev\sapphire\boost_1_46_1\boost/asio/detail/reactive_socket_recv_op.hpp(48) : while compiling class template member function 'bool boost::asio::detail::reactive_socket_recv_op_base::do_perform(boost::asio::detail::reactor_op *)' 
     with 
     [ 
      MutableBufferSequence=boost::asio::mutable_buffers_1 
     ] 
     C:\dev\sapphire\boost_1_46_1\boost/asio/detail/reactive_socket_recv_op.hpp(71) : see reference to class template instantiation 'boost::asio::detail::reactive_socket_recv_op_base' being compiled 
     with 
     [ 
      MutableBufferSequence=boost::asio::mutable_buffers_1 
     ] 
     C:\dev\sapphire\boost_1_46_1\boost/asio/detail/reactive_socket_service_base.hpp(227) : see reference to class template instantiation 'boost::asio::detail::reactive_socket_recv_op' being compiled 
     with 
     [ 
      MutableBufferSequence=boost::asio::mutable_buffers_1, 
      Handler=boost::asio::detail::wrapped_handler,boost::_bi::list3>,boost::arg<1>,boost::arg<2>>>> 
     ] 
     C:\dev\sapphire\boost_1_46_1\boost/asio/stream_socket_service.hpp(263) : see reference to function template instantiation 'void boost::asio::detail::reactive_socket_service_base::async_receive(boost::asio::detail::reactive_socket_service_base::base_implementation_type &,const MutableBufferSequence &,boost::asio::socket_base::message_flags,Handler)' being compiled 
     with 
     [ 
      MutableBufferSequence=boost::asio::mutable_buffers_1, 
      ReadHandler=boost::asio::detail::wrapped_handler,boost::_bi::list3>,boost::arg<1>,boost::arg<2>>>>, 
      Handler=boost::asio::detail::wrapped_handler,boost::_bi::list3>,boost::arg<1>,boost::arg<2>>>> 
     ] 
     C:\dev\sapphire\boost_1_46_1\boost/asio/basic_stream_socket.hpp(708) : see reference to function template instantiation 'void boost::asio::stream_socket_service::async_receive(boost::asio::detail::reactive_socket_service::implementation_type &,const MutableBufferSequence &,boost::asio::socket_base::message_flags,ReadHandler)' being compiled 
     with 
     [ 
      Protocol=boost::asio::ip::tcp, 
      MutableBufferSequence=boost::asio::mutable_buffers_1, 
      ReadHandler=boost::asio::detail::wrapped_handler,boost::_bi::list3>,boost::arg<1>,boost::arg<2>>>> 
     ] 
     ..\..\..\platform_epi\src\connection.cpp(36) : see reference to function template instantiation 'void boost::asio::basic_stream_socket::async_read_some>(const MutableBufferSequence &,ReadHandler)' being compiled 
     with 
     [ 
      Protocol=boost::asio::ip::tcp, 
      Dispatcher=boost::asio::io_service::strand, 
      Handler=boost::_bi::bind_t,boost::_bi::list3>,boost::arg<1>,boost::arg<2>>>, 
      MutableBufferSequence=boost::asio::mutable_buffers_1, 
      ReadHandler=boost::asio::detail::wrapped_handler,boost::_bi::list3>,boost::arg<1>,boost::arg<2>>>> 
     ] 

从我的理解是，错误来自第36行，但我不明白发生了什么。我认为它与byte_transferred在int时用作布尔值有关。如果有人能够澄清这个问题和/或如何解决这个问题，那将是非常棒的！

谢谢！

Answer 1

这是一个Visual Studio特定的警告，它是从Boost的代码发出的，而不是你的。在大多数情况下它可以被忽略。如果您想禁用它，请使用适当的附注。

#pragma warning(disable: 4800) 

它可能已在最新的Boost.ASIO版本中修复。我有1.47安装和有问题的线路不会发出此警告。