diff --git a/src/mapping.h b/src/mapping.h
index c244a1a28f09e73f861eb8872f17804d31639d4a..cdd15dc40267840063437eb8161091b7131c265c 100644
--- a/src/mapping.h
+++ b/src/mapping.h
@@ -63,9 +63,11 @@ extern struct mapping *gc_internal_mapping;
 
 #define MD_KEYPAIRS(MD, HSIZE) \
    ( (struct keypair *)							\
-     DO_ALIGN( PTR_TO_INT(((struct mapping_data *)(MD))->hash + HSIZE),	\
+     DO_ALIGN( PTR_TO_INT(MD) + OFFSETOF(mapping_data, hash) + HSIZE * sizeof(struct keypair *),	\
 	       ALIGNOF(struct keypair)) )
 
+
+
 #ifndef PIKE_MAPPING_KEYPAIR_LOOP
 #define NEW_MAPPING_LOOP(md) \
   for((e=0) DO_IF_DMALLOC( ?0:(debug_malloc_touch(md)) ) ;e<(md)->hashsize;e++) for(k=(md)->hash[e];k;k=k->next)
diff --git a/src/multiset.c b/src/multiset.c
index 4de7b3ba04253c331e64f0c00a7bbf5665b4c486..351662bdd6a01cee3143284726d99edf081d0221 100644
--- a/src/multiset.c
+++ b/src/multiset.c
@@ -161,7 +161,7 @@ union nodeptr {
 #define DELETED_PREV(NODE) INODE (msnode_check (NODE)->i.prev)
 #define DELETED_NEXT(NODE) ((union msnode *) msnode_check (NODE)->i.ind.u.ptr)
 
-#define NODE_AT(MSD, TYPE, POS) ((struct TYPE *) &(MSD)->nodes + (POS))
+#define NODE_AT(MSD, TYPE, POS) ((struct TYPE *)((char*)(MSD) + OFFSETOF(multiset_data, nodes)) + (POS))
 #define NODE_OFFSET(TYPE, POS)						\
   PTR_TO_INT (NODE_AT ((struct multiset_data *) NULL, TYPE, POS))