在Raspbian上使用C++上的线程，不能编译

Question

#include <iostream>
#include <thread>
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>

void error(const char *msg)
{
    perror(msg);
    exit(1);
}

int serverTask(int port){
    int n;
    char buffer[256];
    /* Socket File Descriptors */
    int socketFd, socketFdNew;
    socklen_t clientLength;

    struct sockaddr_in serverAddress, clientAddress;

    /* TCP Socket */
    socketFd = socket(AF_INET, SOCK_STREAM, 0);
    if(socketFd < 0){
        error("ERROR opening socket\n");
    }

    /* Fills serverAddress with zeroes */
    bzero((char *) &serverAddress, sizeof(serverAddress));

    /* ServerAddress configuration */
    serverAddress.sin_family = AF_INET;
    serverAddress.sin_addr.s_addr = INADDR_ANY;
    serverAddress.sin_port = htons(port);

    /* Biding socket to server address */
    if(bind(socketFd, (struct sockaddr *) &serverAddress,sizeof(serverAddress)) < 0){
        error("ERROR on binding");
    }

    /* Listen for incoming connections, 5 is the number of queued devices */
    listen(socketFd,5);

    /* accept freezes the running thread until a client is found */
    clientLength = sizeof(clientAddress);
    socketFdNew = accept(socketFd, (struct sockaddr *) &clientAddress, &clientLength);
    if (socketFd < 0){
        error("ERROR on accept");
    }

    /* Fill buffer with zeroes */
    bzero(buffer,256);

    /* Reads up to 255 characters in the socket */
    n = read(socketFdNew, buffer, 255);
    if (n < 0){
        error("ERROR reading from socket");
    }

    printf("Received: %s\n",buffer);

    /* Responds with placeholder value */
    n = write(socketFdNew,"40.12\n",7);
    if (n < 0){
        error("ERROR writing to socket");
    }
    close(socketFdNew);
    close(socketFd);
    return 0;
}

int main()
{
    std::thread serverTask(7000);

    std::cout <<"Hello World!\n";

    serverTask.join();
    return 0;
}

因此，我尝试使用c++11，然后使用g++-wall-std=c++0x-pthread-o“main”“main.cpp”重新编译，得到以下结果：

在包含于/usr/include/c++/4.6/thread：39：0,from main.cpp：2：/usr/include/c++/4.6/functional：在成员函数中'void std::_bind_result<_result,_functor(_bound_args...)>::__call(std::tuple<_args...>&&,std::_index_tuple<_index...>,typename std::_bind_result<_result,,_functor=int,_bound_args={},typename std::_bind_result<_result,_functor(_bound_args...)>::_enable_if_void<_result>::type=int]':/usr/include/C++/4.6/function:1378:24:实例化自'std::_bind_result<_result，_functor(_bound_args...)>::result_type}，std::_bind_result<_result，_functor(_bound_args...)>::result_type=void]“/usr/include/C++/4.6/thread:117:13:实例化自'void std::thread::_impl<_callable>::_m_run()[with_callable=std::_bind_result]'main.cpp:86:1:从这里实例化/usr/include/c++/4.6/functional:1287:4:error:'((std::_bind_result*)this)->std::_bind_result::_m_f'不能用作函数编译失败。

我最后的办法是安装G++4.9。安装完成后，我尝试使用g++-4.9-wall-std=gnu++0x-pthread-o“main”“main.cpp”，得到以下结果：

在文件include from/usr/include/c++/4.9/thread:39:0、from main.cpp:2:/usr/include/c++/4.9/functional：在'struct std::_bind_simple':/usr/include/c++/4.9/thread:140:47:required from'std::thread::thread(_callable&&,_args&&...)[with_callable=int；_args={}]'main.cpp:79:29:required from able(_args...)>::type result_type；^/usr/include/c++/4.9/functional:1695:9:错误：“class std::result_of”_m_invoke(_index_tuple<_indexes...>)中没有名为“type”的类型^编译失败。

现在我很困惑，我不知道我做错了什么。

#include <iostream>
#include <thread>
#include <stdio.h>


int serverTask(int port){
    return 0;
}

int main()
{
    std::thread serverTask(7000);


    std::cout <<"Hello World!\n";

    serverTask.join();
    return 0;
}

结果保持不变：

g++-4.9-wall-std=gnu++0x-pthread-o“test”“test.cpp”（在目录：/home/pi/tempserver中）包含在/usr/include/c++/4.9/thread:39:0,from test.cpp:2:/usr/include/c++/4.9/functional：在'struct std::_bind_simple'的实例化中：/usr/include/c++/4.9/thread:140:47:required from'std::thread::thread(_callable&&,C++/4.9/functional:1665:61:错误：“class std::result_of”typedef typename result_of<_callable(_args...)>::type result_type中没有名为“type”的类型；^/usr/include/c++/4.9/functional:1695:9:错误：“class std::result_of”_m_invoke(_index_tuple<_indexes...>)中没有名为“type”的类型^编译失败。

Answer 1

这一行：

std::thread serverTask(7000);

声明一个名为ServerTask的变量，并尝试传递7000作为要在线程中运行的函数的名称。但是7000不是函数。不幸的是，G++在这里给出了非常神秘的错误消息。

你可能是说：

std::thread foo(serverTask, 7000);