c++ - 包含 boost/thread.cpp 时出现编译错误

Question

我有以下代码使用 Boost ASIO 设置 TCP 客户端。这是我的代码改编自 Boost 文档的 chat example .

class AsioCommunicationService {
AsioCommunicationService::AsioCommunicationService(
        boost::asio::io_service& io_service,
        tcp::resolver::iterator endpoint_iterator)
    : io_service_(io_service),
      socket_(io_service)
{
    tcp::endpoint endpoint = *endpoint_iterator;
    socket_.async_connect(endpoint,
    boost::bind(&AsioCommunicationService::handle_connect, this,
    boost::asio::placeholders::error, ++endpoint_iterator));
}

void AsioCommunicationService::handle_connect(const boost::system::error_code& error,
        tcp::resolver::iterator endpoint_iterator)
{
    if (!error)
    {
      boost::asio::async_read(socket_,
          boost::asio::buffer(read_msg_.data(), LampMessage::header_length),
          boost::bind(&AsioCommunicationService::handle_read_header, this,
          boost::asio::placeholders::error));
    }
}
}


class Connection
{
    //init io_service, query, resolve, iterator here
    boost::asio::io_service io_service;
    boost::asio::ip::tcp::resolver resolver(io_service);
    boost::asio::ip::tcp::resolver::query query(host, service);
    boost::asio::ip::tcp::resolver::iterator endpoint_iterator =
  resolver.resolve(query);


    m_session = std::shared_ptr<AsioCommunicationService>(
            new AsioCommunicationService(io_service, iterator));

    //start new thread for io_service.run --> GOT AN ERROR when include boost/thread.hpp
    boost::thread t(boost::bind(&boost::asio::io_service::run, &io_service));

    //this synchronous command would work, but it's blocking the program. I don't want that.
    //io_service.run();
}

当然，我需要包含 boost/thread 才能在类 Connection 中声明变量 t。但是当我这样做时，我得到了这个错误

#include <boost/thread.hpp>
//ERROR: In function ‘boost::thread&& boost::move(boost::thread&&)’:
///usr/include/boost/thread/detail/thread.hpp:349:16: error: invalid initialization of reference of type ‘boost::thread&&’ from expression of type ‘boost::thread’
//In file included from /usr/include/boost/thread/detail/thread_heap_alloc.hpp:17:0,
//             from /usr/include/boost/thread/detail/thread.hpp:13,
//             from /usr/include/boost/thread/thread.hpp:22,
//             from /usr/include/boost/thread.hpp:13,
//             from /home/son/dev/logistics/src/frameworks/networkService/NetworkConnection.cpp:13:
///usr/include/boost/thread/pthread/thread_heap_alloc.hpp: In function ‘T* boost::detail::heap_new(A1&&) [with T = boost::detail::thread_data<void (*)()>, A1 = void (*&)()]’:
///usr/include/boost/thread/detail/thread.hpp:130:95:   instantiated from here
///usr/include/boost/thread/pthread/thread_heap_alloc.hpp:24:47: error: cannot bind ‘void (*)()’ lvalue to ‘void (*&&)()’
///usr/include/boost/thread/detail/thread.hpp:43:13: error:   initializing argument 1 of ‘boost::detail::thread_data<F>::thread_data(F&&) [with F = void (*)()]’

如果我删除对 boost/thread.hpp 的包含，并通过对 io_service.run() 的简单调用替换对 t 的声明，它将编译并工作；我想知道这个编译错误是否与 boost 版本有关。如果有任何帮助，我正在使用 Boost ASIO 1.42、Ubuntu 11.04 和 Eclipse。提前谢谢你。

Answer 1

我写了一个包含单个 include 指令的文件:

#include <boost/thread.hpp>

• g++-4.5.4 -std=c++0x -I/usr/include/boost-1_42 -c 给出了您提到的错误。
• g++-4.6.3 -std=c++0x -I/usr/include/boost-1_42 -c 一样
• g++-4.7.1 -std=c++0x -I/usr/include/boost-1_42 -c 给出了更多错误
• g++-4.7.1 -std=c++0x -I/usr/include/boost-1_49 -c 没有一个错误
• g++-4.6.3 和 g++-4.5.4 使用 boost 1.49 也能正常工作

所以我真的建议您为此使用更新版本的 boost。您不必在系统范围内安装它，而是可以为单个用户安装它。所以你不依赖于 ubuntu 包。

要手动安装boost，我建议你按照Getting Started on Unix Variants指南:

1. 解压boost_1_50_0.tar.bz2到一些临时源目录和 cd 进入那个
2. Build and install使用 ./bootstrap.sh --prefix=${HOME}/boost_1_50 && ./b2 install
3. Compile您的应用程序使用 -I ${HOME}/boost_1_50 获取正确的 header
4. 在 linking 时将 ${HOME}/boost_1_50/lib/libboost_thread.a 作为参数包含在内你的申请

使用静态 libboost_thread.a 而不是动态 libbtoost_thread.so 将确保您不必担心定位库来启动您的应用程序。您需要的来自 boost 的所有内容都将包含在您的主二进制文件中。