This variable is used by the debugger when it displays the stack frames. Open frames are made by the system and are normally not shown by the debugger. However if
*print-open-frames*
is set to
t
then the open frames are displayed. It is unlikely that you need to examine open frames: their use is connected with implementation details.
USER 52 > (setq dbg:*print-open-frames* t)
T
USER 53 > (car 2)
Error: Cannot take CAR of 2
1 (abort) return to top loop level 0.
Type :c followed by a number to proceed
USER 54 : 1 > :b 3
Open frame (5)
Open frame (5)
Call to CAR-FRAME :
LispWorks User Guide and Reference Manual - 21 Dec 2011