diff --git a/eval.c b/eval.c
index 6bb2c927..30b6553f 100644
--- a/eval.c
+++ b/eval.c
@@ -2252,8 +2252,7 @@ sexp sexp_make_opcode (sexp ctx, sexp name, sexp op_class, sexp code,
     sexp_opcode_data(res) = data;
     sexp_opcode_data2(res) = data2;
     sexp_opcode_func(res) = func;
-    sexp_opcode_name(res)
-      = strndup(sexp_string_data(name), sexp_string_length(name)+1);
+    sexp_opcode_name(res) = strdup(sexp_string_data(name));
   }
   return res;
 }
diff --git a/sexp.c b/sexp.c
index 2f4388cb..e732005e 100644
--- a/sexp.c
+++ b/sexp.c
@@ -135,7 +135,7 @@ sexp sexp_register_type (sexp ctx, sexp name, sexp fb, sexp flb, sexp flo, sexp
     sexp_type_size_base(type) = sexp_unbox_fixnum(sb);
     sexp_type_size_off(type) = sexp_unbox_fixnum(so);
     sexp_type_size_scale(type) = sexp_unbox_fixnum(sc);
-    sexp_type_name(type) = strndup(sexp_string_data(name), sexp_string_length(name)+1);
+    sexp_type_name(type) = strdup(sexp_string_data(name));
     res = sexp_make_fixnum(sexp_type_tag(type));
   }
   return res;