When does access date get set on tty device

[David McVicar]

Question:

At what point does the st_atime field in the inode get updated when writing
to a tty device?

1.) When the read() system call completes?
2.) When the char written is put on the tty output queue? 
3.) When the char written is actually sent to the device?
4.) It depends?


Problem: We have 300 baud devices that take too long to print reports and 
 	 our auto-logout daemon detects an old access time and
	 no cpu usage for that tty and terminates the user's processes.


Thanks in advance,
Dave McVicar
-- 
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    David J. McVicar 		...!uunet!prcrs!mcvic
   PRC Realty Systems 
   McLean, VA   22102