diff --git a/include/pattern.h b/include/pattern.h
index b512d9d..1242430 100644
--- a/include/pattern.h
+++ b/include/pattern.h
@@ -163,7 +163,9 @@ typedef struct pattern_chain_s pattern_chain;
 liblex_result pattern_compile(pattern_node** root, char* expression);
 /**
  * Frees a pattern NFA allocated by pattern_compile.
+ * @param root the root node to start freeing from.
+ * @return LIBLEX_SUCCESS if all goes well, otherwise some other liblex_result.
  */
-void pattern_free(pattern_node* root);
+liblex_result pattern_free(pattern_node* root);
 
 #endif