add comment on slap_dummy_bv

diff --git a/servers/slapd/attr.c b/servers/slapd/attr.c
index cdfb3a2fe57eb6a11668fe312d7d7b539c8d0265..63973e03cfa53ec2271214579cb3558f4eec0f52 100644 (file)
--- a/servers/slapd/attr.c
+++ b/servers/slapd/attr.c
@@ -46,6 +46,10 @@ attr_free( Attribute *a )
        if ( a->a_nvals && a->a_nvals != a->a_vals ) {
                ber_bvarray_free( a->a_nvals );
        }
+       /* a_vals may be equal to slap_dummy_bv, a static empty berval;
+        * this is used as a placeholder for attributes that do not carry
+        * values, e.g. when proxying search entries with the "attrsonly"
+        * bit set. */
        if ( a->a_vals != &slap_dummy_bv ) {
                ber_bvarray_free( a->a_vals );
        }