A write may be atomic, but prints and printfs go via the stdio layer (or in newer perls, via the perlio layer), which will perform buffering and does writes as much as possible in fixed sized blocks (typically 1, 2 or 8k). Which could mean a single is actually performed as two writes. Or two prints will be done as one write.

If you want to be safe, you always do: lock, seek, print, unlock.

As for pointers, consult Stevens' "Advanced programming in the UNIX environment", IMO, a more useful book for a Perl programmer than all "Perl book"s combined. Afterall, where C is portable assembler, Perl is portable UNIX.

Abigail

In reply to Re: OT (Perhaps) File Locking by Abigail-II
in thread OT (Perhaps) File Locking by Anonymous Monk

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