PHP Manual: preg_last_error

function preg_last_error_msg(): string

Returns the error message of the last PCRE regex execution.

This function has no parameters.

Returns the error message on success, or "No error" if no error has occurred.

Example #1 preg_last_error_msg() example

<?php

preg_match('/(?:\D+|<\d+>)*[!?]/', 'foobar foobar foobar');

if (preg_last_error() !== PREG_NO_ERROR) {
    echo preg_last_error_msg();
}

?>

The above example will output:

Backtrack limit exhausted

preg_last_error_msg