1 files changed, 5 insertions, 1 deletions
diff --git a/generic/tclIOGT.c b/generic/tclIOGT.c
index 2381c3c..215c6c7 100644
--- a/generic/tclIOGT.c
+++ b/generic/tclIOGT.c
@@ -379,7 +379,11 @@ ExecuteCallback(
     unsigned char *resBuf;
     Tcl_InterpState state = NULL;
     int res = TCL_OK;
-    Tcl_Obj *command = TclDuplicatePureObj(dataPtr->command);
+    Tcl_Obj *command = TclDuplicatePureObj(
+	interp, dataPtr->command, &tclListType);
+    if (!command) {
+	return TCL_ERROR;
+    }
     Tcl_Interp *eval = dataPtr->interp;
 
     Tcl_Preserve(eval);