woops, went beyond what I could, I will put this in a few replies...
change of having corrupt data.
One good strategy is to move the locking away from the data file altogether by using a semaphore file. Consider the following:
use Fcntl qw(:flock);
my $file = 'data.file';
my $SEMAPHORE = "$file.lck";
open(S, ">$SEMAPHORE) || die "Foo ($!)";
open(FH, "+<$file") || die "Foofoo ($!)";
# Muck with file
This solves a few problems. First, this allows you to ensure you get a lock when you open a file only for reading. Some systems will not give an exclusive lock on files (which is why you open the semaphore file for write) which were opened only for write only. This gets around that issue. And, by removing the issue of locking completely off the actual data file, you can use one semaphore file to lock multiple files, or directories. And, by removing the locking from the data file you reduce the risk of saying one morning "My hit counter reset itself!".
Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
Read Where should I post X? if you're not absolutely sure you're posting in the right place.
Please read these before you post! —
Posts may use any of the Perl Monks Approved HTML tags:
You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
- a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
Link using PerlMonks shortcuts! What shortcuts can I use for linking?
See Writeup Formatting Tips and other pages linked from there for more info.
| & || & |
| < || < |
| > || > |
| [ || [ |
| ] || ] ||