-ALL-FRAMES = 0 means count windows on all visible and iconified frames.
-If ALL-FRAMES is any other value, count only the selected frame.
-
-If optional third argument DEVICE is nil or omitted, count frames
-on all devices.
-If a device, count frames only on that device.
-If a device type, count frames only on devices of that type.
-Otherwise, count frames only on the selected device."
+WHICH-FRAMES = `visible' means include windows on all visible frames.
+WHICH-FRAMES = 0 means include windows on all visible and iconified frames.
+WHICH-FRAMES = t means include windows on all frames including invisible frames.
+If WHICH-FRAMES is any other value, count only the selected frame.
+
+The optional third argument WHICH-DEVICES further clarifies on which
+devices to search for frames as specified by WHICH-FRAMES. This value
+is only meaningful if WHICH-FRAMES is non-nil.
+If nil or omitted, search all devices on the selected console.
+If a device, only search that device.
+If a console, search all devices on that console.
+If a device type, search all devices of that type.
+If `window-system', search all devices on window-system consoles.
+Any other non-nil value means search all devices."