编写一个简单的http server（Linux, gcc）

#include <iostream>
#include <pthread.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/socket.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>

using namespace std;
bool stop = false;


void *thread_run(void *arg)
{
    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    int fd;
    addr.sin_family = AF_INET;
    addr.sin_port = htons(8081);
    addr.sin_addr.s_addr = INADDR_ANY;
    if((fd = socket(AF_INET, SOCK_STREAM, 0))==-1)
    {
        std::cerr<<"Unable to Open the Socket"<<endl;
        stop = true;
        return NULL;
    }
    if (bind(fd, (struct sockaddr*)(&addr), sizeof(addr)) != 0)
    {
        std::cerr<<"Unable to bind the Socket"<<endl;
        stop = true;
        return NULL;
    }
    if (listen(fd, 50) == -1)
    {
        std::cerr<<"Unable to listen the Socket"<<endl;
        stop = true;
        return NULL;
    }
    while(true){
        sockaddr client_addr;
        unsigned int nLength;
        int fdc = accept(fd, &client_addr, &nLength);
        if (fdc == -1){
            cerr<<"Unable to Connect with the client"<<endl;
            return NULL;
        } else{
            char *request = new char[1000];
            memset(request, 0, 1000);
            read(fdc, request, 1000);
            cout<<request<<endl;
            char buf[] = "HTTP/1.1 200 OK\r\nServer: HTTP Server BY Zhengsq"
                    "\r\nContent-Type: text/html;charset=gb2312\r\n\r\n"
                    "<h1>This is The Server By zhengsq</h1>";
            write(fdc, buf, strlen(buf));
            close(fdc);
            delete[] request;
        }
    }
}

void child_thread()
{
    pthread_t t;
    pthread_attr_t attr;
    if (pthread_attr_init(&attr) != 0)
        std::cerr << "Unable to launch a thread\n";
    if(pthread_create(&t, &attr, thread_run, NULL) != 0)
        std::cerr << "Unable to launch a thread\n";
    if(pthread_attr_destroy(&attr) != 0)
        std::cerr << "Unable to launch a thread\n";
    if(pthread_detach(t) != 0)
        std::cerr << "Unable to launch a thread\n";
}

int main() {
    child_thread();
    while(!stop)
    {
        sleep(1000);
    }
    return 0;
}

上述代码非常简单，专门开启一个线程用于处理socket，主线程sleep

上面到代码包括：开启线程到基本过程，注意线程的执行函数用到了函数指针 void *(*)(void *)

socket开启server端的一般步骤：

1、int fd = socket(AF_INET, SOCK_STREAM, 0)，得到一个socket的handle（或者可以称之为指针）

2、bind（fd, &addr， sizeof(addr)）;

3、listen(fd, 4);

4、循环接受请求accept()

上面到步骤也符合建立一个server的一般逻辑，开辟一个通道，绑定通道到地址，监听通道，从通道接受请求，把数据通过通道送走……