Does the dbx debugger work?

[wallen at sdics.UUCP]

Couldn't one assist dbx with some ioctl()s to turn of write access
(or read access) to certain pages that contained the variables you
wanted to trace?  When the program tried to access that page, it
would stop with a fault.  Then dbx would decide if the faulting address
was one of interest or not.  If so, halt and interact with the
user, otherwise (or after a continue) turn write (or read) access
for the page back on, single step the faulting instruction,
turn the access back off and then run.  Then the program should
run at full steam except where it pinged on pages with traced
variables.

Mark R Wallen
Institute for Cognitive Science
UC San Diego

wallen at ucsd.edu