3 files changed, 7 insertions, 7 deletions
diff --git a/src/collections.c b/src/collections.c
index a4ac744..6a3488b 100644
--- a/src/collections.c
+++ b/src/collections.c
@@ -64,7 +64,7 @@ void*
 lilv_collection_get(const LilvCollection* collection,
                     const LilvIter*       i)
 {
-	return zix_tree_get((ZixTreeIter*)i);
+	return zix_tree_get((const ZixTreeIter*)i);
 }
 
 /* Constructors */
diff --git a/src/zix/tree.c b/src/zix/tree.c
index 844adb9..9915e89 100644
--- a/src/zix/tree.c
+++ b/src/zix/tree.c
@@ -612,7 +612,7 @@ zix_tree_find(const ZixTree* t, const void* e, ZixTreeIter** ti)
 }
 
 ZIX_API void*
-zix_tree_get(ZixTreeIter* ti)
+zix_tree_get(const ZixTreeIter* ti)
 {
 	return ti ? ti->data : NULL;
 }
@@ -658,13 +658,13 @@ zix_tree_rend(ZixTree* t)
 }
 
 ZIX_API bool
-zix_tree_iter_is_end(ZixTreeIter* i)
+zix_tree_iter_is_end(const ZixTreeIter* i)
 {
 	return !i;
 }
 
 ZIX_API bool
-zix_tree_iter_is_rend(ZixTreeIter* i)
+zix_tree_iter_is_rend(const ZixTreeIter* i)
 {
 	return !i;
 }
diff --git a/src/zix/tree.h b/src/zix/tree.h
index f89d9e5..4b6e039 100644
--- a/src/zix/tree.h
+++ b/src/zix/tree.h
@@ -86,7 +86,7 @@ zix_tree_find(const ZixTree* t, const void* e, ZixTreeIter** ti);
    Return the data associated with the given tree item.
 */
 ZIX_API void*
-zix_tree_get(ZixTreeIter* ti);
+zix_tree_get(const ZixTreeIter* ti);
 
 /**
    Return an iterator to the first (smallest) element in @a t.
@@ -104,7 +104,7 @@ zix_tree_end(ZixTree* t);
    Return true iff @a i is an iterator to the end of its tree.
 */
 ZIX_API bool
-zix_tree_iter_is_end(ZixTreeIter* i);
+zix_tree_iter_is_end(const ZixTreeIter* i);
 
 /**
    Return an iterator to the last (largest) element in @a t.
@@ -122,7 +122,7 @@ zix_tree_rend(ZixTree* t);
    Return true iff @a i is an iterator to the reverse end of its tree.
 */
 ZIX_API bool
-zix_tree_iter_is_rend(ZixTreeIter* i);
+zix_tree_iter_is_rend(const ZixTreeIter* i);
 
 /**
    Return an iterator that points to the element one past @a i.