[NTLUG:Discuss] Last time mail was read.

[MadHat]

On Dec 8, 2003, at 1:02 PM, Rusty Haddock wrote:
> MadHat wrote:
>> On Dec 8, 2003, at 10:19 AM, Rusty Haddock wrote:
>>> Paul Ingendorf wrote:
>>>> Why wouldn't this also show the last time mail was recieved?
>>>
>>> Because the '-c' option shows the last time the 'status time' of
>>> the file changed, not the modification time, which would be the
>>> last time mail was received or the USER's inbox was updated.
>>>
>>
>> correct and does an MTA not update the mailbox?
>
> Yes it does but not necessarily upon "reading" the mailbox.

So the MTA delivers mail (sendmail, postfix, qmail).  A new mail 
message comes in and updates your mailbox, so it has to write the new 
messages to your mailbox, therefore updating the file and changing the 
ctime.  This would also be the case when checking your mail, depending 
on the pop/imap daemon you are using and whether or not it is updating 
the file.  It ios possible to read your mail without updating the 
mailbox.

>
>> From the man pages:

Of what?

>
>        Traditionally,  st_ctime  is changed by writing or by set-
>        ting inode information (i.e., owner,  group,  link  count,
>        mode, etc.).
>
> This would probably happen when the MTA is reading the inbox file,
> links to or changes the access permissions, so that it can perform
> its reading on the file without the file changing underneath it.
>
> Sorry, y'all are just getting a bit of conjecture at this point
> 'cause I don't have the time to go digging through the sources to
> explain how it's done in detail.  ;-(