Returns the result entry identifier for the first entry
on success and FALSE on
error.
Entries in the LDAP result are read sequentially using
the ldap_first_entry() and
ldap_next_entry() functions.
ldap_first_entry() returns the entry identifier for first
entry in the result. This entry identifier is then supplied
to ldap_next_entry() routine to get
successive entries from the result.
See also ldap_get_entries().