diff --git a/src/window.c b/src/window.c
index 925a1471..c6409e1 100644
--- a/src/window.c
+++ b/src/window.c
@@ -7147,6 +7147,20 @@
     list_append_number(list, 0);
 }
 
+    win_T *
+win_id2wp(typval_T *argvars)
+{
+    win_T	*wp;
+    tabpage_T   *tp;
+    int		id = get_tv_number(&argvars[0]);
+
+    FOR_ALL_TAB_WINDOWS(tp, wp)
+	if (wp->w_id == id)
+	    return wp;
+
+    return NULL;
+}
+
     int
 win_id2win(typval_T *argvars)
 {