===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/tmux/format.c,v
retrieving revision 1.143
retrieving revision 1.144
diff -u -r1.143 -r1.144
--- src/usr.bin/tmux/format.c	2017/07/07 14:39:45	1.143
+++ src/usr.bin/tmux/format.c	2017/07/27 10:42:05	1.144
@@ -1,4 +1,4 @@
-/* $OpenBSD: format.c,v 1.143 2017/07/07 14:39:45 nicm Exp $ */
+/* $OpenBSD: format.c,v 1.144 2017/07/27 10:42:05 nicm Exp $ */
 
 /*
  * Copyright (c) 2011 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -1405,6 +1405,10 @@
 		format_add(ft, "pane_top", "%u", wp->yoff);
 		format_add(ft, "pane_right", "%u", wp->xoff + wp->sx - 1);
 		format_add(ft, "pane_bottom", "%u", wp->yoff + wp->sy - 1);
+		format_add(ft, "pane_at_left", "%d", wp->xoff == 0);
+		format_add(ft, "pane_at_top", "%d", wp->yoff == 0);
+		format_add(ft, "pane_at_right", "%d", wp->xoff + wp->sx == wp->window->sx);
+		format_add(ft, "pane_at_bottom", "%d", wp->yoff + wp->sy == wp->window->sy);
 	}
 
 	format_add(ft, "pane_in_mode", "%d", wp->screen != &wp->base);