//网络编程--客户端
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>#include <sys/types.h>
#include <sys/socket.h>
#include <pthread.h>
#include <netinet/in.h>
#include <arpa/inet.h>/*强调：当客户端连接服务器时，服务器会产生一个新的文件描述符（套接字）与客户端交互，这个新的套接字不是服务器端的监听套接字套接字是全双工的，在一个网络管道中的两端，每端都可以进行读写操作。*/typedef struct _recvmodel
{int st;struct sockaddr_in * addr;
} RecvModel;//send message
void * send_thread(void *arg)
{if (arg == NULL){printf("param is not allow NULL!\n");return NULL;}int st = *(int *) arg;char buf[1024] = { 0 };while (1){read(STDIN_FILENO, buf, sizeof(buf));if (send(st, buf, strlen(buf), 0) == -1){printf("send failed ! error message %s\n", strerror(errno));return NULL;}memset(buf, 0, sizeof(buf));}return NULL;
}//recv message
void * recv_thread(void * arg)
{if (arg == NULL){printf("param is not allow NULL!\n");return NULL;}RecvModel * model = (RecvModel *) arg;int flag = 0;char buf[1024] = { 0 };while (1){flag = recv(model->st, buf, sizeof(buf), 0);if (flag == 0){printf("对方已经关闭连接！\n");return NULL;} else if (flag == -1){printf("recv failed ! error message : %s\n", strerror(errno));return NULL;}printf("from %s:%s", inet_ntoa(model->addr->sin_addr), buf);memset(buf, 0, sizeof(buf));}return NULL;
}int main(int arg, char *args[])
{//打开socketint st = socket(AF_INET, SOCK_STREAM, 0);if (st == -1){printf("open socket failed! error message:%s\n", strerror(errno));return -1;}//定义IP地址结构struct sockaddr_in addr;memset(&addr, 0, sizeof(addr));//设置TCP/IP连接addr.sin_family=AF_INET;//设置端口号addr.sin_port = htons(8080);//设置允许连接地址addr.sin_addr.s_addr = inet_addr("192.168.1.102");//connect serverint numx = connect(st, (struct sockaddr *) &addr, sizeof(addr));if (numx == -1){printf("connect server failed ! error message :%s\n", strerror(errno));goto END;}RecvModel model;model.st = st;model.addr = &addr;//开启多线程--线程1接收消息，线程2发送消息
    pthread_t thr1, thr2;if (pthread_create(&thr1, NULL, send_thread, &st) != 0){printf("create thread failed ! \n");goto END;}if (pthread_create(&thr2, NULL, recv_thread, &model) != 0){printf("create thread failed ! \n");goto END;}pthread_join(thr1, NULL);pthread_join(thr2, NULL);END: close(st);return 0;
}

//网络编程--服务端
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>#include <sys/types.h>
#include <sys/socket.h>
#include <pthread.h>
#include <netinet/in.h>
#include <arpa/inet.h>typedef struct _recvmodel
{int st;struct sockaddr_in * addr;
} RecvModel;//send message
void * send_thread(void *arg)
{if (arg == NULL){printf("param is not allow NULL!\n");return NULL;}int st = *(int *) arg;char buf[1024] = { 0 };while (1){read(STDIN_FILENO, buf, sizeof(buf));if (send(st, buf, strlen(buf), 0) == -1){printf("send failed ! error message %s\n", strerror(errno));return NULL;}memset(buf, 0, sizeof(buf));}return NULL;
}//recv message
void * recv_thread(void * arg)
{if (arg == NULL){printf("param is not allow NULL!\n");return NULL;}RecvModel * model = (RecvModel *) arg;int flag = 0;char buf[1024] = { 0 };while (1){flag = recv(model->st, buf, sizeof(buf), 0);if (flag == 0){printf("对方已经关闭连接！\n");return NULL;} else if (flag == -1){printf("recv failed ! error message : %s\n", strerror(errno));return NULL;}printf("from %s:%s", inet_ntoa(model->addr->sin_addr), buf);memset(buf, 0, sizeof(buf));}return NULL;
}int main(int arg, char *args[])
{//short port = atoi(args[1]);//打开socketint st = socket(AF_INET, SOCK_STREAM, 0);if (st == -1){printf("open socket failed! error message:%s\n", strerror(errno));return -1;}//设置系统地址可重用int on = 1;if (setsockopt(st, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1){printf("setsockpot failed ! error message %s\n", strerror(errno));goto END;}//定义IP地址结构struct sockaddr_in addr;memset(&addr, 0, sizeof(addr));//设置TCP/IP连接addr.sin_family = AF_INET;//设置端口号addr.sin_port = htons(8080);//设置允许连接地址addr.sin_addr.s_addr = htonl(INADDR_ANY);//bind ipif (bind(st, (struct sockaddr *) &addr, sizeof(addr)) == -1){printf("bind ip failed ! error message :%s\n", strerror(errno));goto END;}//监听连接if (listen(st, 20) == -1){printf("listen failed ! error message :%s\n", strerror(errno));goto END;}//接收客户端连接（阻塞）struct sockaddr_in client_addr;memset(&client_addr, 0, sizeof(client_addr));socklen_t client_addrlen = sizeof(client_addr);    //强调：这里的client_addrlen并不是为了在函数中设置client_addrlen的值，而是通过client_addrlen的值来判断client_addr是一个什么类型的结构，    //所以这里client_addrlen设置为0是错误的，必须是struct sockaddr_in这个结构的大小，不然返回值不正确int client_st = accept(st, (struct sockaddr *) &client_addr,&client_addrlen);if (client_st == -1){printf("accept failed ! error message :%s\n", strerror(errno));goto END;}RecvModel model;model.st = client_st;model.addr = &client_addr;printf("accept by=%s\n",inet_ntoa(client_addr.sin_addr));//开启多线程--线程1接收消息，线程2发送消息
    pthread_t thr1, thr2;if (pthread_create(&thr1, NULL, send_thread, &client_st) != 0){printf("create thread failed ! \n");goto END;}if (pthread_create(&thr2, NULL, recv_thread, &model) != 0){printf("create thread failed ! \n");goto END;}pthread_join(thr1, NULL);pthread_join(thr2, NULL);//关闭客户端管道
    close(client_st);END: close(st);return 0;
}

.SUFFIXES:.c .o
CC=gcc
SRCS1=mserver.c
SRCS2=mclient.c
OBJS1=$(SRCS1:.c=.o)
OBJS2=$(SRCS2:.c=.o)
EXEC1=mserv
EXEC2=mclistart:$(OBJS1) $(OBJS2)$(CC) -o $(EXEC1) $(OBJS1) -lpthread$(CC) -o $(EXEC2) $(OBJS2) -lpthread@echo "^_^ ------ OK ------ ^_^"
.c.o:$(CC) -Wall -g -o $@ -c $<
clean:rm -f $(OBJS1)rm -f $(OBJS2)rm -f $(EXEC1)rm -f $(EXEC2)

小结：这段升级版程序花费3小时，出现一个错误提示：" Transport endpoint is not connected"，我仔细查找资料，网上说是socket套接字不对，可我程序中套接字是正确的，我没有办法，但是我有一个成功的程序，就是第一版socket程序，我将原来的socket程序复制到我的新程序中，一句句替换，终于发现这个问题问题：我缺少addr.sin_family = AF_INET;//将网络地址类型设置为TCP/IP协议；这句代码。缺少这段代码是导致报错的主要原因。另外注意我代码中强调的内容--网络管道是全双工的