从不同的线程写入boost :: asio socket(write to boost::asio socket from different threads)

 在我们的应用程序中，我们使用Boost库（和ASIO进行网络通信）。 
 
 最近，我们发现如果我们通过相同的套接字从不同的线程发送数据，我们的客户端应用程序就会接收数据。 
 
 小测试突出问题： 
 
#include <stdio.h>
#include <boost/thread.hpp>
#include <boost/asio.hpp>

void send_routine(boost::shared_ptr<boost::asio::ip::tcp::socket> s, char c)
{
  std::vector<char> data(15000, c);
  data.push_back('\n');

  for (int i=0; i<1000; i++)
    boost::asio::write(*s, boost::asio::buffer(&data[0], data.size()));
}


int main()
{
  using namespace boost::asio;
  using namespace boost::asio::ip;

  try {
    io_service io_service;
    io_service::work work(io_service);

    const char* host = "localhost";
    const char* service_name = "18000";

    tcp::resolver resolver(io_service);
    tcp::resolver::query query(tcp::v4(), host, service_name);
    tcp::resolver::iterator iterator = resolver.resolve(query);

    auto socket = boost::shared_ptr<tcp::socket>(new tcp::socket(io_service));
    socket->connect(*iterator);

    boost::thread t1(send_routine, socket, 'A');
    boost::thread t2(send_routine, socket, 'B');
    boost::thread t3(send_routine, socket, 'C');

    t1.join();
    t2.join();
    t3.join();
  }
  catch (std::exception& e) {
    printf("FAIL: %s\n", e.what());
  }
    return 0;
}
 
 所以，我们在这里创建套接字，连接到localhost:18000并启动3个线程，这些线程将写入套接字。 
 
 在不同的终端窗口中，我运行nc -l -p 18000 | tee out.txt | sort | uniq | wc -l nc -l -p 18000 | tee out.txt | sort | uniq | wc -l nc -l -p 18000 | tee out.txt | sort | uniq | wc -l 。 我期望3作为输出，但它在网络流中返回超过100“不同的字符串”（因此，数据已损坏）。 但它适用于小缓冲区大小（例如，如果我们将更改15000到80 ）。 
 
 所以，问题是：它是ASIO库的正确行为吗？ 另一个：如何解决它？ 我应该在send_routine函数中使用mutex send_routine （还是有其他解决方案）？ 

In our application we use Boost libraries (and ASIO for network communications). 
 
Recently, we discovered that if we're sending our data from different threads via same socket, our client application is receiving garbaged data.
 
Small test to highlight the issue:
 
#include <stdio.h>
#include <boost/thread.hpp>
#include <boost/asio.hpp>

void send_routine(boost::shared_ptr<boost::asio::ip::tcp::socket> s, char c)
{
  std::vector<char> data(15000, c);
  data.push_back('\n');

  for (int i=0; i<1000; i++)
    boost::asio::write(*s, boost::asio::buffer(&data[0], data.size()));
}


int main()
{
  using namespace boost::asio;
  using namespace boost::asio::ip;

  try {
    io_service io_service;
    io_service::work work(io_service);

    const char* host = "localhost";
    const char* service_name = "18000";

    tcp::resolver resolver(io_service);
    tcp::resolver::query query(tcp::v4(), host, service_name);
    tcp::resolver::iterator iterator = resolver.resolve(query);

    auto socket = boost::shared_ptr<tcp::socket>(new tcp::socket(io_service));
    socket->connect(*iterator);

    boost::thread t1(send_routine, socket, 'A');
    boost::thread t2(send_routine, socket, 'B');
    boost::thread t3(send_routine, socket, 'C');

    t1.join();
    t2.join();
    t3.join();
  }
  catch (std::exception& e) {
    printf("FAIL: %s\n", e.what());
  }
    return 0;
}
 
So, we create socket here, connect to localhost:18000 and start 3 threads which will write to the socket.
 
In different terminal window, I run nc -l -p 18000 | tee out.txt | sort | uniq | wc -l. I expect 3 as output, but it returns more then 100 "different strings" in the network stream (so, data is corrupted). But it works with small buffer sizes (if we'll change 15000 to 80, for example).
 
So, the question is: is it a correct behavior of ASIO library? And another: how to fix it? Should I use mutex inside my send_routine function (or there is another solution)?

原文：https://stackoverflow.com/questions/11581978