diff --git a/simple_protobuf.h b/simple_protobuf.h
index b3151b3..8fa23c7 100644
--- a/simple_protobuf.h
+++ b/simple_protobuf.h
@@ -18,7 +18,7 @@ SIMPLE_PB* read_pb_into(FILE* fp, SIMPLE_PB* spb);
 
 int set_pb(FILE* fp, uint32_t* items_len, uint32_t struct_len, void* target);
 
-//uint32_t struct_size, uint32_t items_cnt, void* item_addr1, void* item_addr2...
+// items_len = align_struct(uint32_t struct_size, uint32_t items_cnt, void* item_addr1, void* item_addr2...)
 uint32_t* align_struct(uint32_t struct_size, uint32_t items_cnt, ...);
 
 #endif
\ No newline at end of file