Basic file I/O in C?

I have a past exam question like that:





Consider the following C code assuming that filename is a plain text file containing the following string:





0123456789





and none of the function calls fail, buffers are big enough, etc...








int fd1, fd2, fd3;


char buf1 = 'x', buf2 = 'x', buf3 = 'x';





fd1 = open("filename", O_RDONLY);


fd2 = dup(fd1);


fd3 = open("filename", O_RDONLY);


lseek(fd1, 4L, SEEK_SET);


lseek(fd2, 2L, SEEK_SET);


lseek(fd3, 7L, SEEK_SET);


read(fd1, %26amp;buf1, 1);


read(fd2, %26amp;buf2, 1);


read(fd3, %26amp;buf3, 1);








So,what will be the content of buf1,buf2,buf3. And explain why.





Can someone help me,please.

Basic file I/O in C?
But it wont compile correctly, filename is undefined, and the open functions (plus parameters such as _O_RDONLY) are OS\compiler specific. Thefore buf1, buf2, and buf3 all equal null.