Wizard-level questions

[Dan Bernstein]

In article <16048 at sdcc6.ucsd.edu> cs163wcr at sdcc10.ucsd.edu (I support the U.N.) writes:
> I have been hacking at these questions for a while, using various
> reference books, with no real progress.

That doesn't make them wizard-level questions.

> [1] Can you access a file by its i-node number?  Something like
> 	(for C code) FILE *iopen (int inode, char *mode) ?

With any reasonable efficiency? Not portably.

> [2] With Internet sockets, how does a machine accept()ing a
> 	socket connection know what machine is calling it?

accept() has three parameters, the second of which is filled in with the
address of the calling machine.

> [3] I have a server program that reads my mail and does various
> 	functions.  One thing I would like it to do is send a "write"
> 	message to other users when it gets a letter with subject
> 	"WRITE user", sending the letter body as the message, but I
> 	can't get write to work unless the output is a tty.  How do
> 	I fool write into thinking my pipe is a tty?

You probably mean that the input is a pipe. In any case, use ``pty
write'' in place of ``write''. pty was published in comp.sources.unix
volume 23; the latest version is available via anonymous ftp to
128.122.128.22.

> [4] How did you become a Unix Wizard?

Who are you talking to?

If you define ``wizard'' as someone who can write any program on the
system, the answer should be obvious. Other definitions lead to other
answers.

---Dan