Re: [EXIM] locking vs freezing spool files and a NUL approac…

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Autor: Philip Hazel
Fecha:  
A: Jeffrey Goldberg
Cc: exim-users
Asunto: Re: [EXIM] locking vs freezing spool files and a NUL approach
On Tue, 25 May 1999, Jeffrey Goldberg wrote:

>   (1) Is freezing enough to protect me from harm here, or should I lock
>       the file instead.


Freezing is enough, provided you don't have auto-thaw set (or anything
else going on that might thaw the message).

> (2) Can exim_lock be used on spool files


No. It uses the locking rules that are applied to mailboxes, not to
spool files.

>   (3) Is there any difference (other than starting a subshell or command)
>       between exim_lock and exim -Meb that I should know about.


Yes! The former locks mailboxes, using the (elaborate) rules Exim uses
for mailboxes; the latter locks the spool file, using the (simpler) rule
Exim uses for spool files. The latter rule is: "Open the -D file for
updating (it actually uses O_RDWR+O_APPEND); take out a write lock on
it."

-- 
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.



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