"Unknown modifier 'g' in..." when using preg_match in PHP?

Question

This is the regex I'm trying to use:

/^(\w|\.|-)+?@(\w|-)+?\.\w{2,4}($|\.\w{2,4})$/gim

I found it on this site, and it works great when I try it out there. But as soon as I place it in my code, I get this message:

Warning: preg_match() [function.preg-match]: Unknown modifier 'g' in C:\xampp\htdocs\swebook\includes\classes.php on line 22

Can anyone explain what's wrong, and why it's working on that website and not in my code?

Ostracize

FYI, your regexp is gonna validate OK these type of mails: "[email protected]" and these type of VALID mails will NOT validate: "[email protected]". Last but not least \w is VERY DANGEROUS cause PHP preg uses Perl Compatible Regular Expressions and NOT POSIX like Javascript. If PHP runs on server that is not US/UK localized \w is gonna match also accented letters so you would match "àèìòù@domain.com" has a valid mail. Read here for more details: it.php.net/manual/en/function.preg-replace.php#92443 – Campstool

Answer 1

There is no modifier g for preg_match. Instead, you have to use the preg_match_all function.

So instead of:

preg_match("/^(\w|\.|-)+?@(\w|-)+?\.\w{2,4}($|\.\w{2,4})$/gim", ....)

use:

preg_match_all("/^(\w|\.|-)+?@(\w|-)+?\.\w{2,4}($|\.\w{2,4})$/im", ....)

Rogovy