diff --git a/vm/utilities.hpp b/vm/utilities.hpp
index 94b9de6f48..cea70c0c37 100755
--- a/vm/utilities.hpp
+++ b/vm/utilities.hpp
@@ -27,5 +27,6 @@ inline static void memset_cell(void *dst, cell pattern, size_t size)
 
 vm_char *safe_strdup(const vm_char *str);
 cell read_cell_hex();
+VM_C_API void *factor_memcpy(void *dst, void *src, size_t len);
 
 }