[Sbcl-devel] problem with TIME

[Nathan F. <fr...@cs...>]

I have been having problems with TIME off and on for several months
now.  When attempting to TIME a form, I would sometimes get an
error along the lines of:

"<foo> is not of type (UNSIGNED-BYTE 32)"

in GET-INTERNAL-REAL-TIME.

danb suggested this might be due to some wackiness of the clock on
my computer.  But TIME would sometimes work on my computer and
sometimes would not.  Yesterday I figured out what the problem was.

What happens is this: GET-INTERNAL-REAL-TIME initializes
*INTERNAL-REAL-TIME-BASE-SECONDS* the first time it is called and
bases subsequent calculations off of *I-R-T-B-S*.  But if *I-R-T-B-S*
has not been updated in some time (either by an extremely long-running
computation using TIME or a core being saved after G-I-R-T is called
and used for a while), then G-I-R-T's internal calculations will
overflow their declared (UNSIGNED-BYTE 32)-ness and cause errors.
Problems could also occur with long-running Lisp sessions (on the
order of 50 days or more).

My initial thought was to add a hook on startup which sets *I-R-T-B-S*
to nil, which eliminates the more likely of the two scenarios listed
above.  But *AFTER-SAVE-INITIALIZATIONS* have been renamed and
apparently declared off limits for system code (was there a replacement
for system code's usage?).  And I'm not entirely convinced this is
the best solution.  Thoughts?
-- 
Nathan | From Man's effeminate slackness it begins.  --Paradise Lost