ubuntu下用gcc调试UDP socket～～
GCC真的很强大，这几天调试UDP socket的程序总下意识的以为GCC调试的时候不能接受标准输入，这让我很为难，刚才正巧外面闪电，我于是先用一个小程序试一试，果然推翻我原来浅薄想法：
#include<stdio.h>
int main()
{
int i;
scanf("%d",&i);
printf("get number is: %d\n",i);
return 0;
}
在ubuntu 11.10 下打开终端，用GDB调试:
(gdb) file try.debug
Reading symbols from /home/kl/code/2/try.debug...done.
(gdb) l
1 #include<stdio.h>
2
3 int main()
4 {
5 int i;
6 scanf("%d",&i);
7 printf("get number is: %d\n",i);
8 return 0;
9 }
(gdb) break 6
Breakpoint 1 at 0x804843d: file try.c, line 6.
(gdb) break 7
Breakpoint 2 at 0x8048452: file try.c, line 7.
(gdb) run
Starting program: /home/kl/code/2/try.debug
Breakpoint 1, main () at try.c:6
6 scanf("%d",&i);
(gdb) print i
$1 = 2797556
(gdb) next
1234
Breakpoint 2, main () at try.c:7
7 printf("get number is: %d\n",i);
(gdb) print i
$2 = 1234
(gdb)
在(gdb)模式下，输入next在跳到下一个中断之前会给输入的机会，用print函数证实如上，真的很开心，但翻过头来想，自己又是这么初级。。。于是，我又以这种想法再次调试我的UDP socket程序：
(gdb) file udps.debug
Reading symbols from /home/kl/code/2/udps.debug...done.
(gdb) l
warning: Source file is more recent than executable.
2 #include<netinet/in.h>
3 #include<arpa/inet.h>
4 #include<unistd.h>
5 #include<sys/types.h>
6 #include<sys/socket.h>
7
8 #define lport 4567
9 #define lip "127.0.0.1"
10 int main()
11 {
(gdb)
12 int mysock,len;
13 struct sockaddr_in addr;
14 int i=0;
15 char msg[256];
16
17 int addr_len;
18
19 if((mysock=socket(AF_INET,SOCK_DGRAM,0))<0)
20 {
21 perror("error");
(gdb)
22 exit(1);
23 }
24 else
25 {
26 printf("socket created.\n");
27 printf("socket ID: %d\n",mysock);
28 }
29 addr_len=sizeof(struct sockaddr_in);
30 bzero(&addr,sizeof(addr));
31 addr.sin_family=AF_INET;
(gdb)
32 addr.sin_port=htons(lport);
33 addr.sin_addr.s_addr=inet_addr(lip);
34
35 if(bind(mysock,&addr,sizeof(addr))<0)
36 {
37 perror("connect");
38 exit(1);
39 }
40 else
41 {
(gdb)
42 printf("bind ok.\n");
43 printf("local port: %d\n",lport);
44 }
45 while(1)
46 {
47 bzero(msg,sizeof(msg));
48 len=recvfrom (mysock,msg,sizeof(msg),0,&addr,&addr_len);
49
50 printf("%d: ",i);
51 i++;
(gdb)
52 printf("message form: %s\n",inet_ntoa(addr.sin_addr));
53 printf("message: %s\n\n",msg);
54 sendto(mysock,msg,len,0,&addr,addr_len);
55 }
56 return 0;
57 }
(gdb) break 48
Breakpoint 1 at 0x8048716: file udps.c, line 48.
(gdb) break 50
Breakpoint 2 at 0x8048751: file udps.c, line 50.
(gdb) break 52
Breakpoint 3 at 0x804876b: file udps.c, line 52.
(gdb) break 53
Breakpoint 4 at 0x804878b: file udps.c, line 53.
(gdb) run
Starting program: /home/kl/code/2/udps.debug
socket created.
socket ID: 7
bind ok.
local port: 4567
Breakpoint 1, main () at udps.c:48
48 len=recvfrom (mysock,msg,sizeof(msg),0,&addr,&addr_len);
(gdb) print mysock
$1 = 7
(gdb) print msg
$2 = '\000' <repeats 255 times>
(gdb) next
最后一行输入next后就是运行recvfrom函数了，于是我打开终端运行client程序：
kl@kl-Latitude-D630:~/code/2$ ./udpc socket created. socket id: 3 romote ip: 127.0.0.1 remote port: 4567 hello Input message: hello
client程序运行顺利，输入"hello"成功，但是在server的调试终端始终没有显示，这和我直接运行server和client程序的结果是一样的，没有达到我调试的目的，现在一方面查阅书籍，一方面接受大家的建议，希望能把这个程序整好～～
我的server和client源代码在如下链接中（这是我提的问题，还在解决中，欢迎并感谢点拨一下～～）
http://www.oschina.net/question/437227_51491
继续学习中。。。。