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Both programs will have the file open for append. If both programs write to them, there's no garantee you end up with something that isn't garbage... On sane Unix-like systems, there is a guarantee: you won't get garbage, regardless of the size of your writes. [1] If the log file is opened in append mode and each entry is committed as a single write (system call), Unix file semantics guarantee that the entries will be appended to the file atomically. (For more information see Re^3: Looking for a simple multiprocess-enabled logging module, which quotes the relevant bits of the Single Unix Specification.) See also "All I want to do is append a small amount of text to the end of a file. Do I still have to use locking?" from perlfaq5. Cheers, [1] Provided that your log file resides on a filesystem that supports Unix semantics. Network-mounted filesystems often fall short. Tom Moertel : Blog / Talks / CPAN / LectroTest / PXSL / Coffee / Movie Rating Decoder In reply to Re^2: Exclusive open for append
by tmoertel
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