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From: "J.O. Aho" <user@example.net>
Newsgroups: comp.lang.php
Subject: Re: preg_match(): return vualue
Date: Sat, 28 Nov 2020 10:57:07 +0100
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On 28/11/2020 09.40, alex wrote:
>  From https://www.php.net/manual/en/function.preg-match.php
> Warning  This function may return Boolean FALSE, but may also return a 
> non-Boolean value which evaluates to FALSE. Please read the section on 
> Booleans for more information. Use the === operator for testing the 
> return value of this function.
> 
> That is?

Put is simply you can get a result that is 0 (no result) or false 
(error), these two values are equal if you make a simple comparison of 
the values

var_dump(0 == false); // => bool(true)

If you need to distinguish between error and no result you need to see 
if the values are identical

var_dump(0 === false); // => bool(false)


In theory the error result could happen when you have a string that 
should match what you are looking for, but also include data that causes 
the regex to fail.

See https://www.php.net/manual/en/language.operators.comparison.php for 
more information on comparison operators.

-- 

  //Aho