[Linux]检测socket异常断开--keepalive

#include<stdlib.h>
#include<stdio.h>
#include<netinet/in.h>
#include<netinet/tcp.h>
#include<netdb.h>
#include<sys/socket.h>
#include<sys/types.h>
#include<unistd.h>
#include<fcntl.h>
#include<errno.h>
#include<string.h>

int main(const int argc,char* const argv[])
{
int socket_fd;
struct sockaddr_in name;
struct hostent *hostinfo;
socket_fd = socket(PF_INET,SOCK_STREAM,IPPROTO_TCP);
name.sin_family = AF_INET;
hostinfo = gethostbyname(argv[1]);
if(hostinfo == NULL) return -1;
name.sin_addr = *((struct in_addr*)hostinfo->h_addr);
name.sin_port = htons(atoi(argv[2]));
if(connect(socket_fd,(struct sockaddr*)&name,sizeof(name))==-1) return -2;

char buf[1024];
ssize_t count;
int sock_flag;
int times=0;
sock_flag = fcntl(socket_fd,F_GETFL);
fcntl(socket_fd,F_SETFL,sock_flag|O_NONBLOCK);
//write(socket_fd,"GET /\n",strlen("GET /\n"));

int keepalive = 1;
int keepidle = 5;
int keepinterval = 3;
int keepcount = 2;
if(setsockopt(socket_fd,SOL_SOCKET,SO_KEEPALIVE,&keepalive,sizeof(keepalive))<0) return -3;
if(setsockopt(socket_fd,SOL_TCP,TCP_KEEPIDLE,&keepidle,sizeof(keepidle))<0) return -4;
if(setsockopt(socket_fd,SOL_TCP,TCP_KEEPINTVL,&keepinterval,sizeof(keepinterval))<0) return -5;
if(setsockopt(socket_fd,SOL_TCP,TCP_KEEPCNT,&keepcount,sizeof(keepcount))<0) return -6;

while(true)
{
count=read(socket_fd,buf,1024);
if(count>0) write(STDOUT_FILENO,buf,count);
else if(count==-1 && errno==EAGAIN)
{
printf("%dth sleep 1s\n",++times);
sleep(1);
}
else
{
printf("count=%d,errno=%d\n",count,errno);
break;
}
}
return 0;
}