diff --git a/src/misc1.c b/src/misc1.c
index 632571d..b0589cf 100644
--- a/src/misc1.c
+++ b/src/misc1.c
@@ -3757,7 +3757,7 @@
      * platforms, $HOMEDRIVE and $HOMEPATH are automatically defined for
      * each user.  Try constructing $HOME from these.
      */
-    if (var == NULL || *var == NULL)
+    if (var == NULL || *var == NUL)
     {
 	char_u *homedrive, *homepath;