之前看unix网络编程，shutdown函数读半关闭会丢弃数据的，但是我写了个测试程序，在同一个主机上运行，关闭读这一半后还是可以读到数据，这是为什么？
client
#include <stdio.h>
#include <sys/socket.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
int main(int argc,char ** argv)
{
int fd;
struct sockaddr_in addr;
int ret;
int i;
char buf[256] = {0};
fd = socket(AF_INET,SOCK_STREAM,0);
if(fd < 0){
fprintf(stderr,"socket error\n");
return -1;
}
addr.sin_family = AF_INET;
addr.sin_port = htons(8888);
addr.sin_addr.s_addr = inet_addr("127.0.0.1");
ret = connect(fd,(struct sockaddr*)&addr,sizeof(addr));
if(ret < 0){
fprintf(stderr,"connect error:%s\n",strerror(errno));
close(fd);
return -1;
}
i = 0;
while(1){
#if 1
if(i == 5){
printf("shutdown read\n");
shutdown(fd,SHUT_RD);
}
#endif
if(i == 10){
printf("client break\n");
shutdown(fd,SHUT_WR);
break;
}
write(fd,"1234567890",10);
i++;
memset(buf,0,sizeof(buf));
if((ret = read(fd,buf,sizeof(buf))) >0){
printf("ret=%d,buf:%s\n",ret,buf);
}
sleep(1);
}
sleep(2);
close(fd);
return 0;
}
server
void recive_data(void *p)
{
int fd = *((int *)p);
char buf[256] = {0};
char out_data[256] = {0};
int status = 0;
int ret;
int i = 0;
while(1){
memset(buf,0,sizeof(buf));
if((ret = read(fd,buf,sizeof(buf)))>0){
printf("server buf:%s\n");
}
else{
printf("ret=%d,recv fin\n",ret);
break;
}
i++;
sprintf(out_data,"the %d tims,0987654321\n",i);
ret = write(fd,out_data,strlen(out_data));
if(ret > 0){
printf("server write %d bytes data to client\n",ret);
}
}
close(fd);
//pthread_exit((void *)&status);
return 0;
}
int main(int argc,char **argv)
{
int socketfd = -1;
struct sockaddr_in addr;
struct sockaddr addr_client;
int addr_len;
int ret;
int listenfd = -1;
fd_set rdset;
pthread_t tid;
int status;
socketfd = socket(AF_INET,SOCK_STREAM,0);
if(socketfd < 0){
fprintf(stderr,"socket error:%s \n",strerror(errno));
return -1;
}
addr.sin_family = AF_INET;
addr.sin_port = htons(8888);
addr.sin_addr.s_addr = htonl(INADDR_ANY);
ret =bind(socketfd,(struct sockaddr*)&addr,sizeof(addr));
if(ret < 0){
fprintf(stderr,"bind error:%s\n",strerror(errno));
return -1;
}
listen(socketfd,0);
while(1){
listenfd = accept(socketfd,&addr_client,&addr_len);
if(listenfd < 0){
fprintf(stderr,"accept error:%s\n",strerror(errno));
return -1;
}
printf("listenfd=%d\n",listenfd);
if(pthread_create(&tid,NULL,recive_data,(void *)&listenfd)<0){
fprintf(stderr,"pthread_create error:%s\n",strerror(errno));
return -1;
}
//pthread_join(tid,&status);
}
close(socketfd);
}
运行结果如下
shishaowei@T330A:~/test/IPC/socket/tcp$ ./tcp_server &
[1] 8567
shishaowei@T330A:~/test/IPC/socket/tcp$ ./tcp_client
listenfd=4
server buf:1234567890
server write 22 bytes data to client
ret=22,buf:the 1 tims,0987654321
server buf:1234567890
server write 22 bytes data to client
ret=22,buf:the 2 tims,0987654321
server buf:1234567890
server write 22 bytes data to client
ret=22,buf:the 3 tims,0987654321
server buf:1234567890
server write 22 bytes data to client
ret=22,buf:the 4 tims,0987654321
server buf:1234567890
server write 22 bytes data to client
ret=22,buf:the 5 tims,0987654321
shutdown read
server buf:1234567890
server write 22 bytes data to client
ret=22,buf:the 6 tims,0987654321
server buf:1234567890
server write 22 bytes data to client
ret=22,buf:the 7 tims,0987654321
server buf:1234567890
server write 22 bytes data to client
ret=22,buf:the 8 tims,0987654321
server buf:1234567890
server write 22 bytes data to client
ret=22,buf:the 9 tims,0987654321
server buf:1234567890
server write 23 bytes data to client
client break
ret=0,recv fin
