diff --git a/src/optionstr.c b/src/optionstr.c
index ccba976..259c64c 100644
--- a/src/optionstr.c
+++ b/src/optionstr.c
@@ -3892,9 +3892,11 @@
  * The 'termwinkey' option is changed.
  */
     char *
-did_set_termwinkey(optset_T *args UNUSED)
+did_set_termwinkey(optset_T *args)
 {
-    if (*curwin->w_p_twk != NUL && string_to_key(curwin->w_p_twk, TRUE) == 0)
+    char_u	**varp = (char_u **)args->os_varp;
+
+    if ((*varp)[0] != NUL && string_to_key(*varp, TRUE) == 0)
 	return e_invalid_argument;
 
     return NULL;
diff --git a/src/testdir/gen_opt_test.vim b/src/testdir/gen_opt_test.vim
index 7b0064c..d12191f 100644
--- a/src/testdir/gen_opt_test.vim
+++ b/src/testdir/gen_opt_test.vim
@@ -56,7 +56,6 @@
       \ shiftwidth:	'TODO: fix missing error handling for setglobal',
       \ sidescrolloff:	'TODO: fix missing error handling for setglobal',
       \ tabstop:	'TODO: fix missing error handling for setglobal',
-      \ termwinkey:	'TODO: fix missing error handling for setglobal',
       \ textwidth:	'TODO: fix missing error handling for setglobal',
       \}
 
diff --git a/src/version.c b/src/version.c
index 404ebf5..1701ffb 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    801,
+/**/
     800,
 /**/
     799,