What are some common pitfalls when using preg_match_all in PHP?

One common pitfall when using preg_match_all in PHP is not properly handling the case where the regex pattern does not match anything in the subject string. This can result in unexpected behavior or errors in your code. To solve this issue, you should check if preg_match_all returns a false value before trying to access the matches.

// Check if preg_match_all returns a false value before accessing the matches
$subject = "Hello, World!";
$pattern = "/foo/";
$matches = [];
if (preg_match_all($pattern, $subject, $matches)) {
    // Access the matches array here
    print_r($matches);
} else {
    // Handle the case where the pattern does not match anything
    echo "No matches found.";
}