PHP raising error when parsing regular expression

Question

I have a PHP function to validate e-mail fields. In my PHP file, I receive below error:

Warning: preg_match(): Unknown modifier '_' in C:\xampp\htdocs\validator.inc.php on line 28

My PHP file is:

<?php
define("EMAIL_MASK", "^[-!#$%&'*+/0-9=?A-Z^_a-z{|}~](\.?[-!#$%&'*+/0-9=?A-Z^_a-z{|}~])*@[a-zA-Z](-?[a-zA-Z0-9])*(\.[a-zA-Z](-?[a-zA-Z0-9])*)+$");

(...)

function isEmailValid($email)
{
    return !empty($email) && preg_match(EMAIL_MASK, $email); <---- This is the line raising the error
}

(...)

?>

What am I doing wrong?

Avinash Raj · Accepted Answer · 2014-10-26T16:28:13.187

1

You failed to put the PHP regex delimiters.

define("EMAIL_MASK", "~^[-!#$%&'*+/0-9=?A-Z^_a-z{|}\~](\.?[-!#$%&'*+/0-9=?A-Z^_a-z{|}\~])*@[a-zA-Z](-?[a-zA-Z0-9])*(\.[a-zA-Z](-?[a-zA-Z0-9])*)+$~");
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edited Oct 26 '14 at 16:28

answered Oct 26 '14 at 16:22

Avinash Raj

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you need to escape `~` – Casimir et Hippolyte Oct 26 '14 at 16:24
@CasimiretHippolyte: Also in character classes? – hakre Oct 26 '14 at 16:27
@CasimiretHippolyte thanks.. – Avinash Raj Oct 26 '14 at 16:28
@hakre: yes also in character classes. – Casimir et Hippolyte Oct 26 '14 at 16:30
@hakre yep, once it finds the next `~` symbol, then it considers it as an end delimiter. So we need to escape `~`, even when the symbol is present within the character class. – Avinash Raj Oct 26 '14 at 16:48
Many thanks! I forgot to put the escape character. – Rodri Oct 26 '14 at 18:20

PHP raising error when parsing regular expression

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