linux 下tcp连接超时崩溃问题

1. #include <stdio.h>  
2. #include <stdlib.h>  
3. #include <errno.h>  
4. #include <string.h>  
5. #include <sys/types.h>  
6. #include <netdb.h>  
7. #include <netinet/in.h>  
8. #include <sys/socket.h>  
9. #include <sys/wait.h>  
10. #include <sys/time.h>  
11. #include <unistd.h>  
12. #include <asm/ioctls.h>  
13. #include <signal.h>   
14. #include <fcntl.h>  
15.   
16. #define SERVPORT 13333  
17. #define TIMEOUT_TIME 6  
18.   
19. int main(int argc,char *argv[])  
20. {  
21.         int sockfd;  
22.         int retval;  
23.         int error=-1;  
24.         char *dest_ip;  
25.         int len;  
26.         int ret=0;  
27.         struct sockaddr_in serv_info;  
28.         struct sigaction act,oldact;  
29.         struct timeval tm;  
30.         fd_set rset,wset;  
31.         char buf[1024];  
32.           
33.         if(argc == 2)  
34.         {  
35.                 dest_ip=argv[1];  
36.         }  
37.   
38.         memset(&serv_info,0,sizeof(serv_info));  
39.         serv_info.sin_family = AF_INET;  
40.         serv_info.sin_port = htons(SERVPORT);  
41.         serv_info.sin_addr.s_addr = inet_addr(dest_ip);  
42.         sockfd = socket(PF_INET,SOCK_STREAM,0);  
43.         if(sockfd<0)  
44.         {  
45.                 perror("socket");  
46.                 return 1;  
47.         }  
48.           
49.         if(fcntl(sockfd,F_SETFL,fcntl(sockfd,F_GETFL) | O_NONBLOCK)<0)  
50.         {  
51.                 perror("fcntl");  
52.                 close(sockfd);  
53.                 return 1;  
54.         }  
55.                   
56.           
57.         if(connect(sockfd,(struct sockaddr *)&serv_info,sizeof(struct sockaddr))<0)  
58.         {  
59.                 if(errno != EINPROGRESS)  
60.                 {  
61.                         perror("connect");  
62.                         return 1;  
63.                 }  
64.                 tm.tv_sec = TIMEOUT_TIME;  
65.                 tm.tv_usec = 0;  
66.                 FD_ZERO(&wset);  
67.                 FD_SET(sockfd,&wset);  
68.                 retval = select(sockfd+1,NULL,&wset,NULL,&tm);  
69.                 switch(retval)  
70.                 {  
71.                         case -1:  
72.                                 perror("select");  
73.                                 return 1;  
74.                         case 0:  
75.                                 printf("timeout\n");  
76.                                 break;  
77.                         default:  
78.                                 if(FD_ISSET(sockfd,&wset))  
79.                                 {  
80.                                         if(getsockopt(sockfd,SOL_SOCKET,SO_ERROR,&error,(socklen_t *)&len)<0)  
81.                                         {  
82.                                                 return 1;  
83.                                         }  
84.                                         printf("error=%d\n",error);  
85.                                         if(error==0)  
86.                                         {  
87.                                                 ret=1;  
88.                                         }  
89.                                         else  
90.                                         {  
91.                                                 ret=0;  
92.                                                 errno=error;  
93.                                         }  
94.                                 }  
95.                                 break;  
96.                 }  
97.         }  
98.           
99.         fcntl(sockfd,F_SETFL,fcntl(sockfd,F_GETFL) & O_NONBLOCK); //set back to block mode  
100.           
101.         if(!ret)  
102.         {  
103.                 close(sockfd);  
104.                 perror("connect failed");  
105.                 return 1;  
106.         }  
107.           
108.         sprintf(buf,"%s","hello world!");  
109.           
110.         if(send(sockfd,buf,strlen(buf),0)<0)  
111.         {  
112.                 perror("send");  
113.         }  
114.           
115.         printf("connected\n");  
116.         return 0;          

1. }  

通过设置为超时非阻塞，可不再使程序崩溃