create guid in php

1function guidv4()
2{
3    if (function_exists('com_create_guid') === true)
4        return trim(com_create_guid(), '{}');
5
6    $data = openssl_random_pseudo_bytes(16);
7    $data[6] = chr(ord($data[6]) & 0x0f | 0x40); // set version to 0100
8    $data[8] = chr(ord($data[8]) & 0x3f | 0x80); // set bits 6-7 to 10
9    return vsprintf('%s%s-%s-%s-%s-%s%s%s', str_split(bin2hex($data), 4));
10}