diff --git a/src/optionstr.c b/src/optionstr.c
index b1bb39a62c..ccba9765f6 100644
--- a/src/optionstr.c
+++ b/src/optionstr.c
@@ -3904,17 +3904,16 @@ did_set_termwinkey(optset_T *args UNUSED)
  * The 'termwinsize' option is changed.
  */
     char *
-did_set_termwinsize(optset_T *args UNUSED)
+did_set_termwinsize(optset_T *args)
 {
+    char_u	**varp = (char_u **)args->os_varp;
     char_u	*p;
 
-    if (*curwin->w_p_tws == NUL)
+    if ((*varp)[0] == NUL)
 	return NULL;
 
-    p = skipdigits(curwin->w_p_tws);
-    if (p == curwin->w_p_tws
-	    || (*p != 'x' && *p != '*')
-	    || *skipdigits(p + 1) != NUL)
+    p = skipdigits(*varp);
+    if (p == *varp || (*p != 'x' && *p != '*') || *skipdigits(p + 1) != NUL)
 	return e_invalid_argument;
 
     return NULL;
diff --git a/src/testdir/gen_opt_test.vim b/src/testdir/gen_opt_test.vim
index e855602525..7b0064cfd9 100644
--- a/src/testdir/gen_opt_test.vim
+++ b/src/testdir/gen_opt_test.vim
@@ -57,7 +57,6 @@ let skip_setglobal_reasons = #{
       \ sidescrolloff:	'TODO: fix missing error handling for setglobal',
       \ tabstop:	'TODO: fix missing error handling for setglobal',
       \ termwinkey:	'TODO: fix missing error handling for setglobal',
-      \ termwinsize:	'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 7a0b0ad1db..404ebf5e82 100644
--- a/src/version.c
+++ b/src/version.c
@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    800,
 /**/
     799,
 /**/