• Gisle Vanem (8/8) Apr 23 2003 Programming with X32VM and DMC 8.33 I install an exception
• Larry Brasfield (18/27) Apr 23 2003 Once memory has been corrupted by
• Gisle Vanem (6/16) Apr 24 2003 Thanks for the info. I was a bit uncertain if

"Gisle Vanem" <gvanem eunet.no> writes:

Programming with X32VM and DMC 8.33 I install an exception
handler using  _x32_fault_intercept().

Then in my handler I longjmp() out to a main exception handler
(in case the stack was screwed up before my handler got called).
Before I call _exit(), I print the registers and call only critical exit
handlers.

Q: Is it safe to use longjmp()?

--gv

Larry Brasfield <larry_brasfield snotmail.com> writes:

In article <b87cpd$r9l$1 digitaldaemon.com>, 
Gisle Vanem (gvanem eunet.no) says...
 Programming with X32VM and DMC 8.33 I install an exception
 handler using  _x32_fault_intercept().
 
 Then in my handler I longjmp() out to a main exception handler
 (in case the stack was screwed up before my handler got called).
 Before I call _exit(), I print the registers and call only critical exit
 handlers.
 
 Q: Is it safe to use longjmp()?

Once memory has been corrupted by
stray writes thru bad pointers, (such
as would "screw up" the stack), then
longjump's data structure may also
have been hit and the longjump() may
fail.  However, understanding that any
stack unwinding (dtor calls) will be
bypassed by a longjump(), it is among
the safer things you can do other than
just terminating the process.

If it was crucial, you could add some
redundancy to the longjump struct and
validate it before the longjump().

-- 
-Larry Brasfield
(address munged, s/sn/h/ to reply)

"Gisle Vanem" <gvanem eunet.no> writes:

"Larry Brasfield" <larry_brasfield snotmail.com> wrote:

 Once memory has been corrupted by
 stray writes thru bad pointers, (such
 as would "screw up" the stack), then
 longjump's data structure may also
 have been hit and the longjump() may
 fail.  However, understanding that any
 stack unwinding (dtor calls) will be
 bypassed by a longjump(), it is among
 the safer things you can do other than
 just terminating the process.

Thanks for the info. I was a bit uncertain if
_x32_fault_intercept() required the handler to
return to do some internal house-keeping.
But some test convinced m it's not needed.

--gv