diff --git a/macros/closeserial.sci b/macros/closeserial.sci
index 13a205b..02f67dd 100644
--- a/macros/closeserial.sci
+++ b/macros/closeserial.sci
@@ -1,4 +1,4 @@
 function result=closeserial(h)
-  TCL_EvalStr("set closeresult [catch {close "+string(h)+"}]"); 
-  result=-eval(TCL_GetVar("closeresult"));
+  TCL_EvalStr("set closeresult [catch {close " + h + "}]"); 
+  result = -evstr(TCL_GetVar("closeresult"));
 endfunction