boxp

Arguments: object

Returns t if the argument is a box object and returns nil otherwise.

See the description of the make-box for more information on boxes.

Warning about positions created by the with-boxes and with-positions-and-boxes

boxp should not be called on objects created by the macros with-boxes and with-positions-and-boxes. The return value of those functions is undefined for objects created by the macros because type information for such objects is sacrificed to achieve the non-consing efficiency of stack allocation.

Copyright (c) 1998-2022, Franz Inc. Lafayette, CA., USA. All rights reserved.
This page was not revised from the 10.0 page.
Created 2019.8.20.