网络编程中的一个错误,搞不定,求助大家

yufeng8552

最近搞网络编程,理论是学习了不少,实践起来真不是那么回事,搞了个最简单的TCP协议的Server-Client试验了下,还有一个错误不能搞定,希望有人能指正一下

我的系统是Redhat 9.0+oracle 9.2.0.1
刚装的系统，应该很干净

[root@BillingServer unix]# gcc -o PRG4_1 PRG4_1.C
PRG4_1.C: In function `int main()':
PRG4_1.C:55: invalid conversion from `int*' to `socklen_t*'
PRG4_1.C:69:2: warning: no newline at end of file

1. // server.c
   
2. #include <stdio.h>; /* These are the usual header files */
   
3. 
   
4. #include <strings.h>; /* for bzero() */
   
5. 
   
6. #include <unistd.h>; /* for close() */
   
7. 
   
8. #include <sys/types.h>;
   
9. 
   
10. #include <sys/socket.h>;
    
11. 
    
12. #include <netinet/in.h>;
    
13. 
    
14. #include <arpa/inet.h>;
    
15. 
    
16. #include <netinet/tcp.h>;
    
17. #include <stdlib.h>;
    
18. #include <errno.h>;
    
19. #include <netdb.h>;
    
20. 
    
21. 
    
22. #define PORT 1234 /* Port that will be opened */
    
23. 
    
24. #define BACKLOG 1 /* Number of allowed connections */
    
25. 
    
26. 
    
27. 
    
28. main()
    
29. 
    
30. {
    
31. 
    
32. int listenfd, connectfd; /* socket descriptors */
    
33. 
    
34. struct sockaddr_in server; /* server's address information */
    
35. 
    
36. struct sockaddr_in client; /* client's address information */
    
37. 
    
38. int sin_size;
    
39. 
    
40. 
    
41. 
    
42. /* Create TCP socket */
    
43. 
    
44. if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
    
45. 
    
46. {
    
47. 
    
48. /* handle exception */
    
49. 
    
50. perror("Creating socket failed.");
    
51. 
    
52. exit(1);
    
53. 
    
54. }
    
55. 
    
56. 
    
57. 
    
58. /* set socket can be reused */
    
59. 
    
60. int opt = SO_REUSEADDR;
    
61. 
    
62. setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
    
63. 
    
64. 
    
65. 
    
66. bzero(&server,sizeof(server)); /* fill server with 0s */
    
67. 
    
68. server.sin_family=AF_INET;
    
69. 
    
70. server.sin_port=htons(PORT);
    
71. 
    
72. server.sin_addr.s_addr = htonl (INADDR_ANY);
    
73. 
    
74. if (bind(listenfd, (struct sockaddr *)&server, sizeof(struct sockaddr)) == -1)
    
75. 
    
76. {
    
77. 
    
78. /* handle exception */
    
79. 
    
80. perror("Bind error.");
    
81. 
    
82. exit(1);
    
83. 
    
84. }
    
85. 
    
86. 
    
87. 
    
88. if(listen(listenfd,BACKLOG) == -1)
    
89. 
    
90. {
    
91. 
    
92. /* calls listen() */
    
93. 
    
94. perror("listen() error\n");
    
95. 
    
96. exit(1);
    
97. 
    
98. }
    
99. 
    
100. 
     
101. 
     
102. sin_size = sizeof(struct sockaddr_in);
     
103. 
     
104. 
     
105. if ((connectfd = accept(listenfd,(struct sockaddr *)&client,&sin_size))==-1)
     
106. 
     
107. {
     
108. 
     
109. /* calls accept() */
     
110. 
     
111. perror("accept() error\n");
     
112. 
     
113. exit(1);
     
114. 
     
115. }
     
116. 
     
117. 
     
118. 
     
119. /* prints client's IP */
     
120. 
     
121. printf("You got a connection from %s\n",inet_ntoa(client.sin_addr) );
     
122. 
     
123. /* send to the client welcome message */
     
124. 
     
125. send(connectfd,"Welcome to my server.\n",22,0);
     
126. 
     
127. 
     
128. 
     
129. close(connectfd); /* close connectfd */
     
130. 
     
131. close(listenfd); /* close listenfd */
     
132. 
     
133. }

复制代码

yufeng8552

1. //client.c
   
2. 
   
3. #include <stdio.h>;
   
4. 
   
5. #include <unistd.h>;
   
6. 
   
7. #include <strings.h>;
   
8. 
   
9. #include <sys/types.h>;
   
10. 
    
11. #include <sys/socket.h>;
    
12. 
    
13. #include <netinet/in.h>;
    
14. 
    
15. #include <netdb.h>; /* netbd.h is needed for struct hostent */
    
16. 
    
17. #include <netinet/ip.h>;
    
18. #include <netinet/tcp.h>;
    
19. #include <stdlib.h>;
    
20. #include <errno.h>;
    
21. 
    
22. 
    
23. 
    
24. #define PORT 1234 /* Open Port on Remote Host */
    
25. 
    
26. #define MAXDATASIZE 100 /* Max number of bytes of data */
    
27. 
    
28. 
    
29. 
    
30. int main(int argc, char *argv[])
    
31. 
    
32. {
    
33. 
    
34. int fd, numbytes; /* files descriptors */
    
35. 
    
36. char buf[MAXDATASIZE]; /* buf will store received text */
    
37. 
    
38. struct hostent *he; /* structure that will get information about remote host */
    
39. 
    
40. struct sockaddr_in server; /* server's address information */
    
41. 
    
42. 
    
43. 
    
44. if (argc !=2)
    
45. 
    
46. {
    
47. 
    
48. /* this is used because our program will need one argument (IP) */
    
49. 
    
50. printf("Usage: %s <IP Address>;\n",argv[0]);
    
51. 
    
52. exit(1);
    
53. 
    
54. }
    
55. 
    
56. 
    
57. 
    
58. if ((he=gethostbyname(argv[1]))==NULL)
    
59. 
    
60. {
    
61. 
    
62. /* calls gethostbyname() */
    
63. 
    
64. printf("gethostbyname() error\n");
    
65. 
    
66. exit(1);
    
67. 
    
68. }
    
69. 
    
70. 
    
71. 
    
72. if ((fd=socket(AF_INET, SOCK_STREAM, 0))==-1)
    
73. 
    
74. {
    
75. 
    
76. /* calls socket() */
    
77. 
    
78. printf("socket() error\n");
    
79. 
    
80. exit(1);
    
81. 
    
82. }
    
83. 
    
84. 
    
85. 
    
86. bzero(&server,sizeof(server));
    
87. 
    
88. server.sin_family = AF_INET;
    
89. 
    
90. server.sin_port = htons(PORT); /* htons() is needed again */
    
91. 
    
92. server.sin_addr = *((in_addr *)he->;h_addr); /*he->;h_addr passes "*he"'s info to "h_addr" */
    
93. 
    
94. 
    
95. 
    
96. if(connect(fd, (struct sockaddr *)&server,sizeof(struct sockaddr))==-1)
    
97. 
    
98. {
    
99. 
    
100. /* calls connect() */
     
101. 
     
102. printf("connect() error\n");
     
103. 
     
104. exit(1);
     
105. 
     
106. }
     
107. 
     
108. 
     
109. 
     
110. if ((numbytes=recv(fd,buf,MAXDATASIZE,0)) == -1)
     
111. 
     
112. {
     
113. 
     
114. /* calls recv() */
     
115. 
     
116. printf("recv() error\n");
     
117. 
     
118. exit(1);
     
119. 
     
120. }
     
121. 
     
122. 
     
123. 
     
124. buf[numbytes]='\0';
     
125. 
     
126. printf("Server Message: %s\n",buf); /* it prints server's welcome message */
     
127. 
     
128. 
     
129. 
     
130. close(fd); /* close fd */
     
131. 
     
132. }

复制代码

lenovo

把
int sin_size;
改为
socklen_t sin_size;
编译错误信息说得已经很清楚了。
还有以后把代码排好版，有代码编辑功能的。

yufeng8552

感谢感谢，可能还是理论不清晰，实践中遇到很多问题

socklen_t是个什么类型的数据啊？能否解释一二，多谢多谢

lenovo

原帖由 "yufeng8552" 发表：
感谢感谢，可能还是理论不清晰，实践中遇到很多问题

socklen_t是个什么类型的数据啊？能否解释一二，多谢多谢

socklen_t一般是这个样子。

1. typedef unsigned int      socklen_t;

复制代码

你去/usr/include/sys/socket.h看看就知道了。

mills

好象我用int  也可以的哦是不是系统不一样的啊

yufeng8552

// 重复性服务器,该程序等候客户连接,一旦连接则显示客户的地址,
// 然后接收来自该客户的信息(字符串).每当收到一个字符串,则显示该字符串,
// 并将字符串反转,再将反转的字符发回客户.
// 之后,继续等待接收该客户的信息直至该客户关闭连接.
// 完成与该客户交互后,服务器开始等待下一客户,并重复上述过程.

1. #include <stdio.h>;          /* These are the usual header files */
   
2. 
   
3. #include <string.h>;          /* for bzero() */
   
4. 
   
5. #include <unistd.h>;         /* for close() */
   
6. 
   
7. #include <sys/types.h>;
   
8. 
   
9. #include <sys/socket.h>;
   
10. 
    
11. #include <netinet/in.h>;
    
12. 
    
13. #include <arpa/inet.h>;
    
14. 
    
15. #define PORT 1234   /* Port that will be opened */
    
16. 
    
17. #define BACKLOG 5   /* Number of allowed connections */
    
18. 
    
19. #define MAXDATASIZE 1000  
    
20. 
    
21. 
    
22. 
    
23. void process_cli(int connectfd, sockaddr_in client);
    
24. 
    
25. 
    
26. 
    
27. main()
    
28. 
    
29. {
    
30. 
    
31.         int listenfd, connectfd; /* socket descriptors */
    
32. 
    
33.         struct sockaddr_in server; /* server's address information */
    
34. 
    
35.         struct sockaddr_in client; /* client's address information */
    
36. 
    
37.         socklen_t sin_size;
    
38. 
    
39. 
    
40. 
    
41.         /* Create TCP socket  */
    
42. 
    
43.         if ((listenfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)  
    
44. 
    
45.         {
    
46. 
    
47.                 /* handle exception */
    
48. 
    
49.                 perror("Creating socket failed.");
    
50. 
    
51.                 exit(1);
    
52. 
    
53.         }
    
54. 
    
55. 
    
56. 
    
57.         int opt = SO_REUSEADDR;
    
58. 
    
59.         setsockopt(listenfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
    
60. 
    
61. 
    
62. 
    
63.         bzero(&server,sizeof(server));
    
64. 
    
65.         server.sin_family=AF_INET;
    
66. 
    
67.         server.sin_port=htons(PORT);
    
68. 
    
69.         server.sin_addr.s_addr = htonl (INADDR_ANY);
    
70. 
    
71.         if (bind(listenfd, (struct sockaddr *)&server, sizeof(struct sockaddr)) == -1)
    
72. 
    
73.         {
    
74. 
    
75.                 /* handle exception */
    
76. 
    
77.                 perror("Bind error.");
    
78. 
    
79.                 exit(1);
    
80. 
    
81.         }
    
82. 
    
83. 
    
84. 
    
85.         if(listen(listenfd,BACKLOG) == -1)
    
86. 
    
87.         {  
    
88. 
    
89.                 /* calls listen() */
    
90. 
    
91.                 perror("listen() error\n");
    
92. 
    
93.                 exit(1);
    
94. 
    
95.         }
    
96. 
    
97. 
    
98. 
    
99.         sin_size=sizeof(struct sockaddr_in);
    
100. 
     
101.         while (1)
     
102. 
     
103.         {
     
104. 
     
105.                 if ((connectfd = accept(listenfd,(struct sockaddr *)&client,&sin_size))==-1)
     
106. 
     
107.             {
     
108. 
     
109.                         perror("accept() error\n");
     
110. 
     
111.                         exit(1);
     
112. 
     
113.             }   
     
114. 
     
115.                 process_cli(connectfd, client);
     
116. 
     
117.         }
     
118. 
     
119. 
     
120. 
     
121.         close(listenfd);   /* close listenfd */         
     
122. 
     
123. }
     
124. 
     
125. 
     
126. 
     
127. void process_cli(int connectfd, sockaddr_in client)
     
128. 
     
129. {
     
130. 
     
131.         int num;
     
132. 
     
133.         char recvbuf[MAXDATASIZE], sendbuf[MAXDATASIZE];
     
134. 
     
135. 
     
136. 
     
137.         printf("You got a connection from %s\n",inet_ntoa(client.sin_addr) );
     
138. 
     
139.         /* prints client's IP */
     
140. 
     
141. 
     
142. 
     
143.         while (num = recv(connectfd, recvbuf, MAXDATASIZE,0))
     
144. 
     
145.         {
     
146. 
     
147.                 recvbuf[num] = '\0';
     
148. 
     
149.                 printf("Received client message: %s",recvbuf);
     
150. 
     
151. 
     
152. 
     
153.                 for (int i = 0; i < num - 1; i++)
     
154. 
     
155.                 {
     
156. 
     
157.                         sendbuf[i] = recvbuf[num - i -2];
     
158. 
     
159.             }
     
160. 
     
161.                 sendbuf[num - 1] = '\0';
     
162. 
     
163. 
     
164. 
     
165.                 send(connectfd,sendbuf,strlen(sendbuf),0); /* send to the client welcome message */
     
166. 
     
167.         }
     
168. 
     
169. 
     
170. 
     
171.         close(connectfd); /*  close connectfd */
     
172. 
     
173. }

复制代码

编译出错
PRG6_3.C: In function `int main()':
PRG6_3.C:27: `exit' undeclared (first use this function)
PRG6_3.C:27: (Each undeclared identifier is reported only once for each
   function it appears in.)
PRG6_3.C:116:2: warning: no newline at end of file

lenovo

[quote]原帖由 "mills"]好象我用int  也可以的哦是不是系统不一样的啊[/quote 发表：

是能编译通过，可是有警告，你的难道连警告都没有？

摇滚北京

加多个头函数
#include<stdlib.h>;

最好用sin_size=sizeof(he) 或sin_size=sizeof(server),可能好一点

release

36    }
    37    bzero(&server,sizeof(server));
    38    server.sin_family = AF_INET;
    39    server.sin_port = htons(PORT); /* htons() is needed again */
    40    server.sin_addr = *((in_addr *)he->;h_addr);
    41  /*he->;h_addr passes "*he"'s info to "h_addr" */
    42    if(connect(fd, (struct sockaddr *)&server,sizeof(struct sockaddr))==-1) {
    43  /* calls connect() */
    44    printf("connect() error\n";
    45    exit(1);
    46    }


# gcc -c socketD.c
socketD.c: In function `main':
socketD.c:40: `in_addr' undeclared (first use in this function)
socketD.c:40: (Each undeclared identifier is reported only once
socketD.c:40: for each function it appears in.)
socketD.c:40: parse error before ')' token

我的不知道怎么错？