Re: just curious!

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* Re: just curious!
@ 2005-10-10  2:25 Suma Choudhary
  0 siblings, 0 replies; 4+ messages in thread
From: Suma Choudhary @ 2005-10-10  2:25 UTC (permalink / raw)
  To: glynn; +Cc: linux-c-programming

Thanks a lot.....

I got to know about the utmp file and the terminal device from the strace and ltrace as suggested by David Eduardo.Could even write  a small code to emulate "write".

Didnt know about "mesg" though.

Thanks again
suma

>>> Glynn Clements <glynn@gclements.plus.com> 10/08/05 12:54 PM >>>

Suma Choudhary wrote:

> I was curious to know how the "write" command works.Any IPCs used?

It determines the terminal(s) on which the specified user is logged in
from the utmp file, opens the terminal device for writing, and writes
to it.

Note that the terminal device must be group-writeable (normally
controlled using "mesg y" or "mesg n"). The write command itself is
setgid tty.

-- 
Glynn Clements <glynn@gclements.plus.com>
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^ permalink raw reply	[flat|nested] 4+ messages in thread

* just curious!
@ 2005-10-06 12:11 Suma Choudhary
  2005-10-06 12:41 ` David Eduardo Gómez Noguera
  2005-10-08  7:17 ` Glynn Clements
  0 siblings, 2 replies; 4+ messages in thread
From: Suma Choudhary @ 2005-10-06 12:11 UTC (permalink / raw)
  To: linux-c-programming

Hello all
I was curious to know how the "write" command works.Any IPCs used?

thanks
suma

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: just curious!
  2005-10-06 12:11 Suma Choudhary
@ 2005-10-06 12:41 ` David Eduardo Gómez Noguera
  2005-10-08  7:17 ` Glynn Clements
  1 sibling, 0 replies; 4+ messages in thread
From: David Eduardo Gómez Noguera @ 2005-10-06 12:41 UTC (permalink / raw)
  To: linux-c-programming

On Thu, 2005-10-06 at 17:41 +0530, Suma Choudhary wrote:
> Hello all
> I was curious to know how the "write" command works.Any IPCs used?
> 
> thanks
> suma

*Use the force^source Luke*

you can play with strace and ltrace too
the manpage also helps.

-- 
David Eduardo GÃ³mez Noguera <davidgn@servidor.unam.mx>

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^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: just curious!
  2005-10-06 12:11 Suma Choudhary
  2005-10-06 12:41 ` David Eduardo Gómez Noguera
@ 2005-10-08  7:17 ` Glynn Clements
  1 sibling, 0 replies; 4+ messages in thread
From: Glynn Clements @ 2005-10-08  7:17 UTC (permalink / raw)
  To: Suma Choudhary; +Cc: linux-c-programming

Suma Choudhary wrote:

> I was curious to know how the "write" command works.Any IPCs used?

It determines the terminal(s) on which the specified user is logged in
from the utmp file, opens the terminal device for writing, and writes
to it.

Note that the terminal device must be group-writeable (normally
controlled using "mesg y" or "mesg n"). The write command itself is
setgid tty.

-- 
Glynn Clements <glynn@gclements.plus.com>

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2005-10-10  2:25 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2005-10-10  2:25 just curious! Suma Choudhary
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2005-10-06 12:11 Suma Choudhary
2005-10-06 12:41 ` David Eduardo Gómez Noguera
2005-10-08  7:17 ` Glynn Clements

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