diff --git a/src/os_mswin.c b/src/os_mswin.c
index d199f3e..3ce61bc 100644
--- a/src/os_mswin.c
+++ b/src/os_mswin.c
@@ -2689,6 +2689,7 @@
     ga_init2(&ga, 1, 100);
 
     EnumWindows(enumWindowsGetNames, (LPARAM)(&ga));
+    ga_append(&ga, NUL);
 
     return ga.ga_data;
 }