250+ TOP MCQs on Named and Un-named Pipe Calls and Answers

Linux Debugging questions and answers focuses on Named and Un-named Pipe Calls.1. What is the output of this program?

```
   #include
```
```
   #include
```
```
   int main()
```
```
   {
```
```
       int fd[2];
```
```
       int count;
```
```
       char buffer[6];
```
```
       if( pipe(fd) != 0)
```
```
           perror("pipe");
```
```
       memset(buffer,' ',6);
```
```
       count=write(fd[1],"Linux",6);
```
```
       read(fd[0],buffer,6);
```
```
       printf("%sn",buffer);
```
```
       return 0;put
```
```
   }
```

a) this program will print the string “Linux”
b) this program will print nothing because the buffer is empty
c) segmentation fault
d) none of the mentioned

Answer: a

2. What is the output of this program?

```
   #include
```
```
   #include
```
```
   int main()
```
```
   {
```
```
       int fd[2];
```
```
       int child;
```
```
       char buff[6];
```
```
       if(pipe(fd) != 0)
```
```
           perror("pipe");
```
```
       child=fork();
```
```
       switch(child){
```
```
           case -1 :
```
```
               perror("fork");
```
```
               exit(1);
```
```
           case 0 :
```

               if (write(fd[1],"Linux",6) != 6)

```
                   perror("write");
```
```
                   break;
```
```
               default :
```
```
                   read(fd[0],buff,6);
```
```
                   printf("%sn",buff);
```
```
                   break;
```
```
       }
```
```
       return 0;
```
```
   }
```

a) this program will print the string “Linux”
b) this program will print nothing
c) segmentation fault
d) none of the mentioned

Answer: a

3. What is the output of this program?

```
   #include
```
```
   #include
```
```
   int main()
```
```
   {
```
```
       int fd;
```
```
       char buff[512];
```

       if( mkfifo("/tmp/test_fifo",0666) == -1)

```
           perror("mkfifo");
```

       fd = open("/tmp/test_fifo",O_RDONLY);

```
       read(fd,buff,512);
```
```
       printf("%sn",buff);
```
```
       return 0;
```
```
   }
```

a) this program will print the garbage of 512 bytes
b) this program will print nothing
c) segmentation fault
d) none of the mentioned

Answer: b

4. This program will print the _____ string.

```
   #include
```
```
   int main()
```
```
   {
```
```
       int fd[2];
```
```
       char buff[11];
```
```
       if (pipe(fd) != 0)
```
```
           perror("pipe");
```
```
       write(fd[1],"",11);
```
```
       lseek(fd[0],0,3);
```
```
       read(fd[0],buff,11);
```
```
       printf("%sn",buff);
```
```
       return 0;
```
```
   }
```

a) “”
b) “San”
c) “foundry”
d) none of the mentioned

Answer: a

5. What is the output of this program?

```
   #include
```
```
   int main()
```
```
   {
```

       if (mkfifo("/tmp/test_fifo",0666) != 0)

```
           perror("mkfifo");
```

       if (mkfifo("/tmp/test_fifo",0666) != 0)

```
           perror("mkfifo");
```
```
       return 0;
```
```
   }
```

a) this program will create two named pipes “test_fifo” in the /tmp directory
b) this program will create one named pipe “test_fifo” in the /tmp directory
c) segmentation fault
d) none of the mentioned

Answer: b

6. What is the output of this program?

```
   #include
```
```
   #include
```
```
   int main()
```
```
   {
```
```
       int fd, count;
```
```
       char buff[10];
```

       if (mkfifo("/tmp/test_fifo",0666) != 0)

```
           perror("mkfifo");
```

       fd = open("/tmp/test_fifo",O_RDONLY|O_NONBLOCK);

```
       count = read(fd,buff,10);
```
```
       printf("%dn",count);
```
```
       return 0;
```
```
   }
```

a) 0
b) -1
c) 10
d) none of the mentioned

Answer: a

7. This program will print the value

```
   #include
```
```
   #include
```
```
   int main()
```
```
   {
```
```
       int rfd, wfd, count;
```
```
       char buff[11];
```

       if (mkfifo("/tmp/test_fifo",0666) != 0)

```
           perror("mkfifo");
```

       wfd = open("/tmp/test_fifo",O_WRONLY|O_NONBLOCK);

```
       count = write(wfd,"",11);
```
```
       printf("%dn",count);
```

       rfd = open("/tmp/test_fifo",O_RDONLY|O_NONBLOCK);

```
       count = read(rfd,buff,11);
```
```
       return 0;
```
```
   }
```

a) 0
b) -1
c) 11
d) none of the mentioned

Answer: b

8. What is the output of this program?

```
   #include
```
```
   int main()
```
```
   {
```
```
       int fd[3],count;
```
```
       if (pipe(fd) != 0)
```
```
           perror("pipe");
```
```
       count = write(fd[2],"Hello",6);
```
```
       printf("%dn",count);
```
```
       return 0;
```
```
   }
```

a) 6
b) 0
c) -1
d) segmentation fault

Answer: c

9. In this program the fifo “my_fifo”

```
   #include
```
```
   int main()
```
```
   {
```
```
       if (mkfifo("my_fifo",0666) != 0)
```
```
           perror("mkfifo");
```
```
       return 0;
```
```
   }
```

a) can not be created
b) will be created in present working directory
c) will have the execute permissions
d) none of the mentioned

Answer: b

10. What is the output of this when the pipe is successfully created?

```
    #include
```
```
    int main()
```
```
    {
```
```
        int ret_val;
```
```
        int fd[2];
```
```
        ret_val = pipe(fd);
```
```
        printf("%dn",ret_val);
```
```
        return 0;
```
```
    }
```

a) 0
b) -1
c) 1
d) none of the mentioned

Answer: a

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250+ TOP MCQs on Named and Un-named Pipe Calls and Answers

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