用tcp/IP进行网际互联-套接字API

 1 #include <iostream>
 2 #include <netdb.h>
 3 #include <sys/socket.h>
 4 #include <unistd.h>
 5 
 6 using namespace std;
 7 
 8 int main(void)
 9 {
10     struct protoent *ptr;
11 
12     if(ptr=getprotobyname("udp"))
13     {
14         char **pptr=ptr->p_aliases;
15         cout<<ptr->p_name<<endl;
16 
17         while(*pptr != NULL)
18         {
19             cout<<*pptr<<endl;
20             pptr++;
21         }
22         cout<<ptr->p_proto<<endl;
23     }
24     else
25     {
26         cout<<"error"<<endl;
27     }
28 }

 1 #include <iostream>
 2 #include <unistd.h>
 3 #include <sys/types.h>
 4 #include <netdb.h>
 5 #include <sys/socket.h>
 6 #include <arpa/inet.h>
 7 #include <cstdlib>
 8 
 9  using namespace std;
10  int main(void)
11 {
12     struct hostent *hptr;
13     char str[20];
14     gethostname(str,sizeof(str));
15     if(hptr=gethostbyname(str))
16     {
17         cout<<hptr->h_name<<endl;
18         switch(hptr->h_addrtype)
19         {
20             case AF_INET:
21                 cout<<"AF_INET"<<endl;
22                 break;
23             case AF_INET6:
24                 cout<<"AF_INET6"<<endl;
25                 break;
26             default:
27                 cout<<"else"<<endl;
28                 break;
29         }
30         char **ptr=hptr->h_aliases;
31 
32         while(*ptr != NULL)
33         {
34             cout<<*ptr<<endl;
35             ptr++;
36         }
37 
38         ptr=hptr->h_addr_list;
39         char str[32];
40 
41         while(*ptr != NULL)
42         {
43             cout<<inet_ntop(hptr->h_addrtype,*ptr,str,sizeof(str));
44             ptr++;
45         }
46         cout<<hptr->h_length<<endl;
47     }
48     else
49     {
50         cout<<"error"<<endl;
51     }
52 }
53  

 1 #include <iostream>
 2 #include <netdb.h>
 3 #include <unistd.h>
 4 #include <sys/socket.h>
 5 #include <errno.h>
 6 
 7 using namespace std;
 8 
 9 int main(void)
10 {
11     struct servent *ser_info;
12 
13     if(ser_info=getservbyname("echo","udp"))
14     {
15         char **ptr;
16         cout<<ser_info->s_name<<endl;
17         ptr=ser_info->s_aliases;
18         while(*ptr != NULL)
19         {
20             cout<<*ptr<<endl;
21             ptr++;
22         }
23         cout<<(ser_info->s_port)<<endl;
24         cout<<ser_info->s_proto<<endl;
25     }
26     else
27     {
28         perror("getservbyname:");
29     }
30 }
31