Question

I am using the following methods:

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

I get the following warning:

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)

Here is the complete output as well:

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>>>>
        ]

From my understanding is that the error comes from line 36 but I don’t understand what is happening. I think it has something to do with the bytes_transferred being used as a bool when it is int. If anyone could clarify on this issue and/or how to fix it, it would be superb!

Thanks!

Answer 1

This is a Visual Studio-specific warning, and it’s being emitted from Boost’s code, not yours. It can be ignored in most cases. If you want to disable it, use the appropriate pragma.

#pragma warning(disable: 4800)

It may have been fixed in the latest Boost.ASIO version. I have 1.47 installed and the line in question doesn’t emit this warning.