簡單示例，有不對的地方，歡迎指點。

伺服器端

/*
 ============================================================================
 Name        : sockThreadServer.c
 Author      : gaotong
 Version     :
 Copyright   : Your copyright notice
 Description : Hello World in C, Ansi-style
 ============================================================================
 */

#include <stdio.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <pthread.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <string.h>
#define gettid() syscall(__NR_gettid) //獲得執行緒ID

void * handler_conn(void * arg) {
	char send_str[100];
	int client_sock_fd = *(int *) arg;
	char recv_str[100];
	//printf("thread run success \n");
	while (1) {
		read(client_sock_fd, recv_str, 100);

		//如果對方發來exit 就斷開連線
		if (strcmp(recv_str, "exit") == 0) {
			break;
		}
		printf("receive from %d : %s \n", client_sock_fd, recv_str);
		int id = gettid(); // 得到執行緒ID

		sprintf(send_str, "這是執行緒:%d,你好,client_sock_fd:%d\n", id, client_sock_fd);

		if(write(client_sock_fd, send_str, 100) == -1){
			perror("send error"); //客戶端關閉連線
			break;
		}

		printf("我說: %s \n", send_str);

	}

	free(arg);
	puts("斷開連線\n");
	close(client_sock_fd);
	pthread_exit(0);
}

int main(void) {

	int * client_sockfd;
	int server_len, client_len;
	struct sockaddr_in server_address;
	struct sockaddr_in client_address;
	struct sockaddr_in tempaddr;


	server_address.sin_family = AF_INET;
	server_address.sin_port = htons(1991);
	server_address.sin_addr.s_addr = inet_addr("127.0.0.1");

	//建立一個socket
	int sock_fd = socket(AF_INET, SOCK_STREAM, 0);

	//繫結
	bind(sock_fd, (struct sockaddr *) &server_address, sizeof(server_address));

	listen(sock_fd, 20);

	while (1) {
		pthread_t thread; //每連線一個client 就建立一個執行緒

		puts("監聽等待：…………\n");
		//client_sockfd 需要作為一個指標，傳給執行緒。以便每個執行緒都能控制自己的連線
		client_sockfd = (int *) malloc(sizeof(int));

		client_len = sizeof(client_address);

		//int accept (int socket, struct sockaddr *addr, socklen_t *length_ptr)
		*client_sockfd = accept(sock_fd, (struct sockaddr *) &client_address,
				(socklen_t *) &client_len);

		printf("client connected ! %d \n", *client_sockfd);

		pthread_create(&thread, NULL, handler_conn, client_sockfd);

		puts("執行緒建立\n");
	}

	return EXIT_SUCCESS;
}
 

客戶端：

/*
 ============================================================================
 Name        : sockThreadClient.c
 Author      : gaotong
 Version     :
 Copyright   : Your copyright notice
 Description : Hello World in C, Ansi-style
 ============================================================================
 */

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

int client_sockfd;
char recv_str[100];

void * getMsg(void * arg){
	int test;
	while( (test =read(client_sockfd, recv_str, 100)) != EOF){

		if(test == 0) //伺服器關閉連線
			break;
		if(test == -1)
		{
			printf("read error!");
			break;
		}
		printf("收到伺服器訊息:%s\n",recv_str);
	}

	close(client_sockfd);
	pthread_exit(0);
}

int main(void) {

	char char_send[100];

	//建立一個socket
	client_sockfd = socket(AF_INET, SOCK_STREAM , 0);

	struct sockaddr_in serverAddr; //伺服器地址
	serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
	serverAddr.sin_family = AF_INET;
	serverAddr.sin_port = htons(1991);

	connect(client_sockfd,(struct sockaddr *)&serverAddr, sizeof(serverAddr));

	pthread_t pt;
	pthread_create(&pt, NULL, getMsg, NULL);

	while(1){
		gets(char_send); //從控制檯讀入要傳送的資料
		//int send (int socket, void *buffer, size_t size, int flags)
		if(send(client_sockfd, char_send,sizeof(char_send),0) == -1){
			break;
		}
		printf("我對伺服器說:%s\n",char_send );

		if(strcmp(char_send, "exit") == 0){ // 輸入exit 退出
			break;
		}
	}

	close(client_sockfd);

	return EXIT_SUCCESS;
}
 

執行結果：