阻塞IO模型

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<sys/socket.h>
#include<netinet/in.h>
#include<arpa/inet.h>
#include<fcntl.h>
#include<thread> 

#define MaxSize 2048
/*
tcp多线程并发，阻塞IO模式，
缺点：需要对套接字进行轮询读取，效率低。
缺点：当有很多客户端时， 需要开辟大量线程，浪费资源。
*/
void *Task(void *arg)
{
    int sockfd = (long)arg;
    pthread_detach(pthread_self());
    while (1)
    {
        char msg[MaxSize] = { '' };
        int len = recv(sockfd, msg, MaxSize, 0);
        if (len > 0)
        {
            printf("recv %s 
", msg);
            //再发回去。
            send(sockfd, msg, len, 0);
        }
        sleep(1);
    }
    return NULL;
}


int main()
{
    unsigned short port = 8000;

    printf("TCP Server Started at port %d!
", port);

    int sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if(sockfd<0)
    {
        perror("socket");
        exit(-1);
    }

    struct sockaddr_in my_addr;
    bzero(&my_addr, sizeof(my_addr));
    my_addr.sin_family=AF_INET;
    my_addr.sin_port=htons(port);
    my_addr.sin_addr.s_addr=htonl(INADDR_ANY);

    printf("Binding server to port %d
", port);
    int err_log=bind(sockfd, (struct sockaddr*)&my_addr, sizeof(my_addr));
    if (err_log != 0)
    {
        perror("binding");
        close(sockfd);
        exit(-1);
    }

    err_log=listen(sockfd,10);
    if (err_log!=0)
    {
        perror("listen");
        close(sockfd);
        exit(-1);
    }

    printf("Waiting client...
");

    while (1)
    {
        size_t recv_len=0;
        struct sockaddr_in client_addr;
        char cli_ip[INET_ADDRSTRLEN] = "";
        socklen_t cliaddr_len = sizeof(client_addr);
        int NewClient;
        NewClient = accept(sockfd, (struct sockaddr*)&client_addr, &cliaddr_len);
        if (NewClient < 0)
        {
            perror("accept");
            continue;
        }

        inet_ntop(AF_INET, &client_addr.sin_addr, cli_ip, INET_ADDRSTRLEN);
        printf("client ip = %s
", cli_ip);

        //每一个链接，创建一个线程，在线程中对客户端套接字进行读写。
        pthread_t thread_id;
        pthread_create(&thread_id, NULL, &Task, (void *)NewClient);
    }
    close(sockfd);
    return 0;
}