Re^3: Faster locking

Could someone please confirm that Perl would skip trying to acquire a lock when the first 'if' condition is true?

Should I rather place the test in to a nested condition, completely outside of the first?

if ( (1 == 1) || (!flock $lockfile, LOCK_EX | LOCK_NB) )

PS: Things appear to be working as expected, but I would still like to know, for my own peace of mind.

Comment on Re^3: Faster locking Download Code

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Re^4: Faster locking by bbs2web (Acolyte) on Apr 04, 2017 at 08:38 UTC
Okay, so it works as expected: Test code: `#!/usr/bin/perl use strict; use warnings; use Fcntl qw(:flock); open our $lockfile, '<', $0 \|\| die $!; if ( (1 == 1) \|\| (!flock $lockfile, LOCK_EX \| LOCK_NB) ) { print "in loop\n"; sleep 30; if (flock $lockfile, LOCK_EX \| LOCK_NB) { print "locked\n"; } else { print "not locked\n"; } sleep 30; }` [download] First instance: `in loop locked` [download] Second instance: `in loop not locked` [download]	[reply] [d/l] [select]

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Re^4: Faster locking
by bbs2web (Acolyte) on Apr 04, 2017 at 08:38 UTC

Okay, so it works as expected:

Test code:

#!/usr/bin/perl
use strict;
use warnings;
use Fcntl qw(:flock);

open our $lockfile, '<', $0 || die $!;
if ( (1 == 1) || (!flock $lockfile, LOCK_EX | LOCK_NB) ) {
  print "in loop\n";
  sleep 30;
  if (flock $lockfile, LOCK_EX | LOCK_NB) {
    print "locked\n";
  } else {
    print "not locked\n";
  }
  sleep 30;
}
[download]

First instance:

in loop
locked
[download]

Second instance:

in loop
not locked
[download]

[reply]
[d/l]
[select]