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Subject: Re: [PHP-DEV] Bug in preg_match() ?
From: curt@php.net (Curt Zirzow)

* Thus wrote Michael Spector:
> 
> Hi,
> 
> This script:
> 
> <?
>         $line = "Use operator m// for matching strings";
>         $pattern = "m//";
> 
>         if(preg_match("/$pattern/", $line, $match)) {
>                 print $match[0]."\n";
>         }
> ?>
> 
> outputs the following error:
> 
> <br />
> <b>Warning</b>:  Unknown modifier '/' in <b>/home/michael/bug.php</b> on 
> line <b>5</b><br />
> 
> 
> I thought it should find the match "m//" ...
> 
> Can you say, why search of the ending delimiter in a pattern cannot
> be performed in a simple way, as you can see in the attached patch ?

Because of side effects like this:

  $pattern = "Foo//i";
  if(preg_match("/$pattern", $line, $match)) {

With your patch the preg_match has silently turned into a
caseINsensitve search.

Just use preg_quote($pattern, '/');


Curt
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