This PHP code connects to an LDAP server, performs a search for entries with the last name and then sorts and prints them alphabetically. The sorting is done by a custom function called compareEntry, which compares entries based on last names and first names. It uses the LDAP functions to communicate with the server and showcases basic error handling.

The code demonstrates the use of arrays, loops, sorting, and LDAP functions, making it a good example for understanding how to interact with LDAP servers in PHP.