Question

我想用c ++创建多线程mjpeg流，我用单线程成功，但是当我尝试启动＆＃34; stream＆＃34;函数在一个单独的线程中或使用std :: async（我认为async比在这种情况下创建一个线程更好），我不明白为什么，它不起作用。那个函数似乎不是从其他线程开始的。你能帮帮我吗？感谢

streamer.cpp

#include "streamer.h"
#include <cstring>
#include <sys/types.h>
#include <unistd.h>
#include <future>

void Streamer::stream(int socket)
{
    std::string image, buffer;
    int check = send(socket, header.c_str(), header.size(), MSG_NOSIGNAL);
    while (check > 0)
    {
        image = camera->getFrameInByteArray();
        buffer = "--boundary\r\n"
                 "Content-Type: image/jpeg\r\n"
                 "Content-Length: " + std::to_string(image.size()) + "\r\n\r\n" + image;
        check = send(socket, buffer.c_str(), buffer.size(), MSG_NOSIGNAL);
    }
    close(socket);
}

void Streamer::start() {    
    bindChannel();
    listen(socketFileDescriptor, 5);
    socklen_t clientLenght = sizeof(clientAddress);
    while(1) {
        newSocketFileDescriptor = accept(socketFileDescriptor, (struct sockaddr *) &clientAddress, &clientLenght);
        if (newSocketFileDescriptor < 0)
            error("Error accepting request");

        /*If I do this, I can't serve more than one request*/
        std::async(std::launch::async, &Streamer::stream, this, newSocketFileDescriptor);

    }
    close(socketFileDescriptor);
}

void Streamer::error(std::string msg){...}

void Streamer::bindChannel(){...}

Streamer::~Streamer(){...}

Streamer::Streamer(int port, int cameraAddress){...}

编辑：

我尝试以这种方式定义为static和modify stream（）函数：

void Streamer::stream(Camera &cam, int socket)
{
    std::string head =  "HTTP/1.1 200 OK\r\n"
                        "Connection: close\r\n"
                        "Max-Age: 0\r\n"
                        "Expires: 0\r\n"
                        "Cache-Control: no-cache, private\r\n"
                        "Pragma: no-cache\r\n"
                        "Content-Type: multipart/x-mixed-replace;boundary=--boundary\r\n\r\n";

    std::string image, buffer;
    int check = send(socket, head.c_str(), head.size(), MSG_NOSIGNAL);
    while (check > 0)
    {
        image = cam.getFrameInByteArray();
        buffer = "--boundary\r\n"
                 "Content-Type: image/jpeg\r\n"
                 "Content-Length: " + std::to_string(image.size()) + "\r\n\r\n" + image;
        check = send(socket, buffer.c_str(), buffer.size(), MSG_NOSIGNAL);
    }
    close(socket);
}

我试过这些：

//std::thread{Streamer::stream, std::ref(*camera), newSocketFileDescriptor}.detach();
//auto f = std::async(std::launch::async, Streamer::stream, std::ref(*camera), newSocketFileDescriptor);
//std::async(std::launch::async, Streamer::stream, std::ref(*camera), newSocketFileDescriptor);

在所有情况下，我一次只能提供一个请求

在c ++类中启动异步（或线程）方法

0 个答案: