What is the correct syntax for using regular expressions to match specific patterns in PHP?

When using regular expressions in PHP to match specific patterns, you need to use the `preg_match()` function. This function takes a regular expression pattern and a string to search for matches. The pattern should be enclosed in forward slashes (/) and any specific characters or sequences you want to match should be included within the pattern. The `preg_match()` function will return true if a match is found, and false otherwise.

$pattern = "/[0-9]{3}-[0-9]{3}-[0-9]{4}/"; // Regular expression pattern to match phone numbers in the format XXX-XXX-XXXX
$string = "Call me at 123-456-7890"; // String to search for a phone number match

if (preg_match($pattern, $string)) {
    echo "Phone number found!";
} else {
    echo "Phone number not found.";
}