What are some potential pitfalls when using regular expressions in PHP, specifically with the preg_match function?

One potential pitfall when using regular expressions in PHP with the preg_match function is not properly escaping special characters. This can lead to unexpected behavior or errors in the regex pattern matching. To solve this, make sure to use the preg_quote function to escape any special characters in the input string before using it in the regex pattern. 

$input_string = "Special characters like . and * need to be escaped.";
$escaped_input = preg_quote($input_string, '/');
$pattern = '/\b' . $escaped_input . '\b/';

if (preg_match($pattern, $subject)) {
    echo "Match found!";
} else {
    echo "No match found.";
}

Keywords

regular expressions PHP preg_match syntax errors backtracking

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