The ldap_first_attribute() and ldap_next_attribute() functions are used to step through the attributes in an LDAP entry. ldap_first_attribute() takes an entry as returned by ldap_first_entry(3LDAP) or ldap_next_entry(3LDAP) and returns a pointer to memory that must be freed with a call to ldap_memfree(3LDAP).

They also return, in berptr, a pointer to a BerElement it has allocated to keep track of its current position. This pointer should be passed to subsequent calls to ldap_next_attribute() and is used to effectively step through the entry's attributes. This pointer is freed by ldap_next_attribute() when there are no more attributes, that is, when ldap_next_attribute() returns NULL. Otherwise, the caller is responsible for freeing the BerElement pointed to by berptr when it is no longer needed by calling ber_free(3LDAP). When calling ber_free(3LDAP) in this instance, be sure the second argument is '0'.

The attribute names returned are suitable for inclusion in a call to ldap_get_values(3LDAP) to retrieve the attribute's values.

If an error occurs, NULL is returned and the ld_errno field in the ld parameter is set to indicate the error. See ldap_error(3LDAP) for a description of possible error codes.

See attributes(5) for a description of the following attributes:

ldap(3LDAP), ldap_first_entry(3LDAP), ldap_get_values(3LDAP), ldap_error(3LDAP), attributes(5)

The ldap_first_attribute() function alllocates memory that might need to be freed by the caller by means of ber_free(3LDAP).