Sun Directory Server Enterprise Edition 7.0 Developer's Guide
To iterate through all filters that make up a specified filter,
use this function in conjunction with the
slapi_filter_list_next() function.  Filters of the type
LDAP_FILTER_AND, LDAP_FILTER_OR , and LDAP_FILTER_NOT generally
consist of one or more other filters. For example, if the filter
is:   the first filter in this list is:   Call this function to
get the first filter in the list.