php file lock while using file() method

Asked Apr 28 '15 at 12:13

Active Apr 28 '15 at 12:31

Viewed 51 times

$f = fopen($file . '.lock', 'w');
flock($f, LOCK_SH);
$data = file($file);
flock($f, LOCK_UN);
fclose($f);
unlink($file . '.lock');

I saw this as one of the suggestions on this question on locking a file when using file() method to read.

file lock is obtained on $file.'.lock' while file read is done on $file using the file() method.

shouldn't file read be done on $file.lock file on which lock is obtained?

edited Apr 28 '15 at 12:31

asked Apr 28 '15 at 12:13

manas jay

Why don't you use the solution that was provived there? It's exactly what you need. – machineaddict Apr 28 '15 at 12:18
You can try to use LOCK_EX – JustAnotherSimpleProgrammer__ Apr 28 '15 at 12:21
I understand thats a working solution, but I am trying to understand how the locking works in this case. Since lock is on $file.lock while read is done on $file. What if another script writes to $file at the same time that this script is accessing $file? – manas jay Apr 28 '15 at 12:22
@manasjay LOCK_EX is the solution for all your problems. LOCK_EX doesn't allow if another script writes to $file at the same time that this script is accessing $file. – JustAnotherSimpleProgrammer__ Apr 28 '15 at 12:28

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