多进程：

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>#define SER_PORT 8888
#define SER_IP  "192.168.124.242"   //"0.0.0.0"int deal_cli_msg( int newfd, struct sockaddr_in cin);int main(int argc, const char *argv[])
{//创建流式套接字int sfd = socket(AF_INET, SOCK_STREAM, 0);if(sfd < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("socket");return -1;}printf("socket success __%d__\n", __LINE__);//允许端口快速重用                                                                                  int reuse = 1;if(setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)) < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("setsockopt");return -1;}printf("reuseaddr success __%d__\n", __LINE__);//若从命令行传入端口号，则使用传入的端口号，没有传入则使用宏定义的端口号int port =  argc>=2?atoi(argv[1]):SER_PORT;//填充服务器的地址信息结构体，给bind函数使用//真实的地址信息结构体根据地址族指定 AF_INET: man 7 ipstruct sockaddr_in sin;sin.sin_family      = AF_INET;              //必须填AF_INETsin.sin_port        = htons(port);          //端口号的网络字节序，1024～49151sin.sin_addr.s_addr = inet_addr(SER_IP);    //本机IP的网络字节序，ifconfig查看本机IP//127.0.0.1：本地换回IP，只能做本机通信的IP//0.0.0.0 : 代表运行环境中所有可用IP//绑定服务器自身的地址信息if(bind(sfd, (struct sockaddr*)&sin, sizeof(sin)) < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("bind");return -1;}printf("bind success __%d__\n", __LINE__);//将套接字设置为被动监听状态if(listen(sfd, 128) < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("listen");return -1;}printf("listen success __%d__\n", __LINE__);//阻塞等待客户端连接成功，从已完成连接的队列头中获取一个客户端信息，//生成一个新的文件描述符，这个新的文件描述符才是与客户端通信用的文件描述符struct sockaddr_in cin;     //存储获取到的客户端的地址信息socklen_t addrlen = sizeof(cin);int newfd = -1;pid_t pid = 0;while(1){//父进程负责处理客户端连接事件newfd = accept(sfd, (struct sockaddr*)&cin, &addrlen);if(newfd < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("accpet");return -1;}printf("client connect success, [%s:%d] newfd = %d __%d__\n", \inet_ntoa(cin.sin_addr), ntohs(cin.sin_port), newfd, __LINE__);//有客户端连接成功，需要创建子进程负责与客户端通信pid = fork();if( 0 == pid){close(sfd);//子进程中的sfddeal_cli_msg(newfd, cin);break;        //or exit(0);子进程只负责与客户端交互，客户端退出，子进程需要结束}close(newfd);//父进程的newfd；}close(sfd);//父进程中的sfdreturn 0;
}int deal_cli_msg( int newfd, struct sockaddr_in cin)
{char buf[128] = "";ssize_t res = 0;while(1){bzero(buf, sizeof(buf));    //memset(buf, 0, sizeof(buf));//收res = recv(newfd, buf, sizeof(buf), 0);if(res < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("recv");return -1;}else if(0 == res){printf("client [%s:%d] offline  __%d__\n",\inet_ntoa(cin.sin_addr), ntohs(cin.sin_port), __LINE__);break;}printf("[%s:%d] newfd=%d : %s\n", inet_ntoa(cin.sin_addr), ntohs(cin.sin_port), newfd, buf);//发strcat(buf, "*_*");if(send(newfd, buf, sizeof(buf), 0) < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("send");return -1;}printf("send success __%d__\n", __LINE__);}close(newfd);//子进程中的newfdreturn 0;
}

多线程：

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>#define SER_PORT 8888
#define SER_IP  "192.168.124.242"   //"0.0.0.0"int deal_cli_msg( int newfd, struct sockaddr_in cin);int main(int argc, const char *argv[])
{//创建流式套接字int sfd = socket(AF_INET, SOCK_STREAM, 0);if(sfd < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("socket");return -1;}printf("socket success __%d__\n", __LINE__);//允许端口快速重用                                                                                  int reuse = 1;if(setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse)) < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("setsockopt");return -1;}printf("reuseaddr success __%d__\n", __LINE__);//若从命令行传入端口号，则使用传入的端口号，没有传入则使用宏定义的端口号int port =  argc>=2?atoi(argv[1]):SER_PORT;//填充服务器的地址信息结构体，给bind函数使用//真实的地址信息结构体根据地址族指定 AF_INET: man 7 ipstruct sockaddr_in sin;sin.sin_family      = AF_INET;              //必须填AF_INETsin.sin_port        = htons(port);          //端口号的网络字节序，1024～49151sin.sin_addr.s_addr = inet_addr(SER_IP);    //本机IP的网络字节序，ifconfig查看本机IP//127.0.0.1：本地换回IP，只能做本机通信的IP//0.0.0.0 : 代表运行环境中所有可用IP//绑定服务器自身的地址信息if(bind(sfd, (struct sockaddr*)&sin, sizeof(sin)) < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("bind");return -1;}printf("bind success __%d__\n", __LINE__);//将套接字设置为被动监听状态if(listen(sfd, 128) < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("listen");return -1;}printf("listen success __%d__\n", __LINE__);//阻塞等待客户端连接成功，从已完成连接的队列头中获取一个客户端信息，//生成一个新的文件描述符，这个新的文件描述符才是与客户端通信用的文件描述符struct sockaddr_in cin;     //存储获取到的客户端的地址信息socklen_t addrlen = sizeof(cin);int newfd;pthread_t tid;struct Climsg pcli;while(1){//主线程负责处理客户端连接事件newfd = accept(sfd, (struct sockaddr*)&cin, &addrlen);if(newfd < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("accpet");return -1;}printf("client connect success, [%s:%d] newfd = %d __%d__\n", \inet_ntoa(cin.sin_addr), ntohs(cin.sin_port), newfd, __LINE__);//有客户端连接成功，需要创建一个子线程负责与客户端通信pthread_create( &tid, NULL, deal_cli_msg, (void*)&pcli);pthread_detach( tid);}close(sfd);//父进程中的sfdreturn 0;
}//线程回调函数
void* deal_cli_msg( void* arg )
{int newfd = ( (struct Climsg*)arg )->newfd;struct sockaddr_in cin = ( (struct Climsg*)arg)->cin;char buf[128] = "";ssize_t res = 0;while(1){bzero(buf, sizeof(buf));    //memset(buf, 0, sizeof(buf));//收res = recv(newfd, buf, sizeof(buf), 0);if(res < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("recv");return -1;}else if(0 == res){printf("client [%s:%d] offline  __%d__\n",\inet_ntoa(cin.sin_addr), ntohs(cin.sin_port), __LINE__);break;}printf("[%s:%d] newfd=%d : %s\n", inet_ntoa(cin.sin_addr), ntohs(cin.sin_port), newfd, buf);//发strcat(buf, "*_*");if(send(newfd, buf, sizeof(buf), 0) < 0){fprintf(stderr, "__%d__ ", __LINE__);perror("send");return -1;}printf("send success __%d__\n", __LINE__);}close(newfd);//子线程中的newfdpthread_exit( NULL);
}