［solved］一个c语言程序的错误

LaoLiulaoliu

1. 
   
2. #include <stdio.h>
   
3. #include <unistd.h>
   
4. #include <string.h>
   
5. main()
   
6. {
   
7.         int a,lon=3;
   
8.         char pbuf[]="I am your father?";
   
9.         char cbuf[]="sun!";
   
10.         int files[2];
    
11.         if(pipe(files)==-1)
    
12.         {
    
13.                 perror("Failed to creat pipe!");
    
14.         }
    
15.         a=fork();
    
16.         if(a>0)
    
17.         {
    
18.                 write(files[1],pbuf,strlen(pbuf)+1);
    
19.         }
    
20.         else
    
21.                 if(a==0)
    
22.                 {
    
23.                         sleep(2);
    
24.                         printf("%s\n",pbuf);
    
25.                         lon=read(files[0],cbuf,18);
    
26.                         printf("%s\n",pbuf);
    
27.                 }
    
28.                 else
    
29.                 {
    
30.                         perror("Failed to creat a childpid!");
    
31.                 }
    
32.         printf("pid:%d readBuffer is (%d){%s},writeBuffer is {%s}\n",getpid(),lon,cbuf,pbuf);
    
33.         return 1;
    
34. }
    

复制代码

1.ubuntu下的结果：
naiad@artist:/home/programming/OperatingSystem$ ./pipeme
pid:26252 readBuffer is (3){sun!},writeBuffer is {I am your father?}
naiad@artist:/home/programming/OperatingSystem$ I am your father?
r?
pid:26253 readBuffer is (18){I am your},writeBuffer is {r?}

2.gentoo下的结果：
naiad@artist:/home/programming/OperatingSystem$ ./pipeme
pid:26252 readBuffer is (3){sun!},writeBuffer is {I am your father?}
naiad@artist:/home/programming/OperatingSystem$ I am your father?
r?
pid:26253 readBuffer is (18){I am your father?},writeBuffer is {?}

3.Fedora下的结果：
naiad@artist:/home/programming/OperatingSystem$ ./pipeme
pid:26252 readBuffer is (3){sun!},writeBuffer is {I am your father?}
naiad@artist:/home/programming/OperatingSystem$ I am your father?
r?
pid:26253 readBuffer is (18){I am your father?},writeBuffer is {your father?}

4.我的预测：
naiad@artist:/home/programming/OperatingSystem$ ./pipeme
pid:26252 readBuffer is (3){sun!},writeBuffer is {I am your father?}
naiad@artist:/home/programming/OperatingSystem$ I am your father?
I am your father?
pid:26253 readBuffer is (18){I am },writeBuffer is {I am your fahter?}
但是我预测的结果没有出来。请老师们指点。

LaoLiulaoliu

这个程序好像和函数read中的第三个参数有关，小于等于7就没有问题，大于7cbuf和pbuf好像都随机的有问题。

是gcc的问题吗？

swordman

我觉得是数组越界的问题

LaoLiulaoliu

原来这样--越界。