Warning: preg_match() [function.preg-match]: Unknown modifier [duplicate]

Question

I'm getting this error...

Warning: preg_match() [function.preg-match]: Unknown modifier '1' in C:\path-to-plugin.php on line 147

When I run the keyword "Test $2/1 test+word!" through the function below

function my_get_kw_in_content($theKeyword, $theContent)
    {
//ERROR OCCURS NEXT LINE
    return preg_match('/\b' . $theKeyword . '\b/i', $theContent);
    }

I'm assuming that I need to sanitize the keyword to escape the "/" character (and possibly more). I'd appreciate any suggestions you have to sanitize the string before running it through the preg_match.

UPDATE: This appears to work thanks to Thai:

function my_get_kw_in_content($theKeyword, $theContent)
    {
    $theKeyword = preg_quote($theKeyword, '/');
    return preg_match('/\b' . $theKeyword . '\b/i', $theContent);
    }

Marqueritemarques

Answer 1

Use preg_quote to quote regular expression characters.

Like this:

preg_quote($theKeyword, '/');

Where '/' is the delimiter in your regular expression.

Tompion

Thai, I've updated my question with your answer. It appears to be working for me. Can you check my update to insure I'm implementing your answer properly? – Marqueritemarques