多线程的TCP并发服务器的实现步骤：

1，创建一个socket套接字


2，绑定IP地址和端口信息到socket,使用函数bind()
1)IP地址

2）bind

3，设置允许的最大连接数，使用函数listen()

4,等待来自客户端的连接请求，使用函数accept()

5，收发数据，用函数recv()，send()/sendto()或者read(),write()
6，关闭网络连接，close

开始：建立文件

/*DATA:         2018-1-17*AUTHOR:       wg*DESCRIPTION:  多线程TCP服务器*  1，int socket(int domain,int type,int protocol);*  2, int bind(int sockfd,const struct sockaddr *addr,socklen_t addrlen);*  3, int listen(int sockfd,int backlog);*  4, accept(int sockfd,struct sockaddr *addr,socklen_t *addrlen);*  5, read(),write()*/#include <sys/socket.h>
#include <sys/un.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include<netinet/in.h>
#include<unistd.h>
#include <arpa/inet.h>
#include <pthread.h>#define MAX_LISTEN 100
int ad[10];
char buf[128]={0};
struct sockaddr_in server_ip, remote_ip;void *thread_fun(void *arg)
{while(1){printf("read data from client : %s\n",inet_ntoa(remote_ip.sin_addr));memset(buf,0,128);read(ad[(int)arg],buf,128);printf("buf =%s\n",buf);}
return NULL;
}int main()
{int server_len,remote_len;int err,sd;pthread_t tid[10];int i=0;sd=socket(AF_INET,SOCK_STREAM,0);if(sd == -1){printf("create socket failure, errno =%d\n",sd);close(sd);return -1;}server_ip.sin_family =AF_INET;server_ip.sin_port = htons(10086);server_ip.sin_addr.s_addr =htonl(INADDR_ANY);memset(server_ip.sin_zero,0,8);err=bind(sd,(struct sockaddr *)(&server_ip),sizeof(struct sockaddr));if(err==-1){printf("bind error,errno=%d\n",err);close(sd);return err;}err=listen(sd,MAX_LISTEN);if(err == -1){printf("listen error ,errno =%d\n",err);close(sd);return err;}remote_len=sizeof(struct sockaddr);while(1)//listen n client quest{ad[i]=accept(sd,(struct sockaddr *)(&remote_ip),&remote_len);if(ad[i] !=0 ){printf("accept error,errno =%d\n",ad[i]);close(sd);return -2;}err=pthread_create(&tid[i],NULL,thread_fun,(void*)i);if(err !=0){printf("create new thread failure\n");close(ad[i]);}++i;}close(sd);return 0;
}

可循环监听和接收多个客服端的请求。

Tcp客户端创建步骤：
1，创建一个socket，使用函数socket()
2, 设置要连接的服务器地址和端口
3，连接服务器，使用函数connect()
4，收发数据，使用函数recv(),sendto(),或write()和read()
5, 关闭网络连接，close()

创建client.c文件

#include <sys/socket.h>
#include <sys/un.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include<netinet/in.h>
#include<unistd.h>
#include <arpa/inet.h>
#include <pthread.h>char buf[100];
int sd;
struct sockaddr_in server_ip;void *thread_write(void *arg)
{while(1){write(sd,"hello",6);sleep(1);}}void *thread_read(void *arg){while(1){sleep(1);memset(buf,0,100);read(sd,buf,100);printf("client 2 say: %s\n",buf);}
}int main()
{int server_len, remote_len;pthread_t tid_read,tid_write;int err;sd=socket(AF_INET,SOCK_STREAM,0);if(sd == -1){printf("create socket failure");return sd;}server_ip.sin_family =AF_INET;server_ip.sin_port = htons(10086);server_ip.sin_addr.s_addr = htonl(INADDR_ANY);memcpy(server_ip.sin_zero,0,8);err = connect(sd,(struct sockaddr *)(&server_ip),sizeof(struct sockaddr));if(err == -1){printf("connect failure\n");close(sd);return err;}err = pthread_create(&tid_read,NULL,thread_read,NULL);if(err !=0){printf("create read thread failure\n");close(sd);return err;}err = pthread_create(&tid_write,NULL,thread_write,NULL);if(err !=0){printf("create write thread failure\n");close(sd);return err;}pthread_join(&tid_read,NULL);pthread_join(&tid_write,NULL);close(sd);return 0;}