File: st_concurrency

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#!/bin/sh

# running this script intermittently yields
#
#     Magic number checking on storable file failed at ...
#
# but it is difficult to trigger this error 100% reliably
# as would be needed to turn this script into an actual test

perl -I. -x t/st_concurrency st_shared &
perl -I. -x t/st_concurrency st_shared &
perl -I. -x t/st_concurrency st_shared &
perl -I. -x t/st_concurrency st_shared &
wait && exec rm st_shared

#!perl
use strict; use warnings;

use Memoize::Storable;
use Fcntl 'LOCK_EX';

sub rand32 () { int rand 1<<32 }

# the script locks itself to increase the likelihood of the error:
# after releasing the lock, the first process writes to the file
# just as another process acquires the lock and starts to read it
# (but this still does not trigger the error reliably)

open my $fh, $0 or die $!;
flock $fh, LOCK_EX or die $!;

tie my %cache => 'Memoize::Storable', $ARGV[0];
$cache{(rand32)} = rand32;

close $fh;
# vim: ft=perl