diff --git a/cache.h b/cache.h
index 2711048cad..4134f648ec 100644
--- a/cache.h
+++ b/cache.h
@@ -993,6 +993,11 @@ int adjust_shared_perm(const char *path);
  * directory while we were working.  To be robust against this kind of
  * race, callers might want to try invoking the function again when it
  * returns SCLD_VANISHED.
+ *
+ * safe_create_leading_directories() temporarily changes path while it
+ * is working but restores it before returning.
+ * safe_create_leading_directories_const() doesn't modify path, even
+ * temporarily.
  */
 enum scld_error {
 	SCLD_OK = 0,