一个 C 实现最基本的 socket 编程例子

haulm

服务端 service.c

1. #include <stdio.h>
   
2. #include <sys/socket.h>
   
3. #include <netinet/in.h>
   
4. #include <arpa/inet.h>
   
5. #include <netdb.h>
   
6. #include <stdlib.h>
   
7. #include <string.h>
   
8. int port = 17000;
   
9. main ()
   
10. {
    
11.   struct sockaddr_in sin;
    
12.   struct sockaddr_in pin;
    
13.   int sock_descriptor;
    
14.   int temp_sock_descriptor;
    
15.   int size_of_addr;
    
16.   size_of_addr=sizeof(pin);
    
17.   char buf[8192];
    
18.   int i, lenth;
    
19.   sock_descriptor = socket (AF_INET, SOCK_STREAM, 0);
    
20.   bzero (&sin, sizeof (sin));
    
21.   sin.sin_family = AF_INET;
    
22.   sin.sin_addr.s_addr = htonl(INADDR_ANY);
    
23.   sin.sin_port = htons (port);
    
24.   if (bind (sock_descriptor, (struct sockaddr *) &sin, sizeof (sin)) == -1)
    
25.       {
    
26.       perror ("bind!"); exit (1);}
    
27.       if (listen (sock_descriptor, 20) == -1)
    
28.       {
    
29.       perror ("listen!"); exit (1);}
    
30.       printf ("waiting for accepting connections from client\n");
    
31. while (1)
    
32.       {
    
33.         temp_sock_descriptor = accept(sock_descriptor,(struct sockaddr *)&pin,&size_of_addr);
    
34.         if (temp_sock_descriptor == -1)
    
35.       {
    
36.       perror ("call to accept"); }
    
37.       if (recv (temp_sock_descriptor, buf, sizeof (buf), 0) == -1)
    
38.       {
    
39.       perror ("recv!"); exit (1);}
    
40.       printf ("received:%s\n", buf);
    
41.       lenth = strlen (buf);
    
42. for (i = 0; i <= lenth; i++)
    
43.       {
    
44.       buf[i] = toupper (buf[i]);
    
45.       if (send (temp_sock_descriptor, buf, lenth, 0) == -1)
    
46.       {
    
47.       perror ("send!"); exit (1);}
    
48.       }
    
49. close (temp_sock_descriptor);
    
50.       }
    
51. }
    

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客户端 client.c

1. #include <stdio.h>
   
2. #include <sys/socket.h>
   
3. #include <netinet/in.h>
   
4. #include <arpa/inet.h>
   
5. #include <netdb.h>
   
6. #include <string.h>
   
7. #include <stdlib.h>
   
8. char * host_name="127.0.0.1";
   
9. int port=17000;
   
10. void main(int argc,char *argv[])
    
11. {
    
12. char buf[4096];
    
13. char message[1024];
    
14. int socket_descriptor;
    
15. struct sockaddr_in pin;
    
16. struct hostent *server_host_name;
    
17. char *message_str="hello,network";
    
18. if(argc<2)
    
19. {printf("send default srting.\n");
    
20. }else{
    
21. message_str=argv[1];
    
22. }
    
23. if((server_host_name=gethostbyname(host_name))==0)
    
24. {
    
25. perror("cant resolving localhost\n");
    
26. exit(1);
    
27. }
    
28. bzero(&pin,sizeof(pin));
    
29. pin.sin_family=AF_INET;
    
30. pin.sin_addr.s_addr=htonl(INADDR_ANY);
    
31. pin.sin_addr.s_addr=((struct in_addr *)(server_host_name->h_addr))->s_addr;
    
32. pin.sin_port=htons(port);
    
33. if((socket_descriptor=socket(AF_INET,SOCK_STREAM,0))==-1)
    
34. {perror("Error opening socket\n");
    
35. exit(1);
    
36. }
    
37. if(connect(socket_descriptor,(void *)&pin,sizeof(pin))==-1)
    
38. {
    
39. perror("cant connecting to server");
    
40. exit(1);
    
41. }
    
42. printf("send message %s to server ...\n",message_str);
    
43. if (send(socket_descriptor,message_str,strlen(message_str),0)==-1)
    
44. {
    
45. perror("cant send message\n");
    
46. exit(1);
    
47. }
    
48. printf("waiting for response from server\n");
    
49. if (recv(socket_descriptor,buf,sizeof(buf),0)==-1)
    
50. {
    
51. perror("cant receive response\n");
    
52. exit(1);
    
53. }
    
54. printf("\nResponse from server:\n\n%s\n",buf);
    
55. close(socket_descriptor);
    
56. }

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