Re: i386 int3 handling, running vs stepping

Doug Evans
2009-02-02T20:03:23Z

On Sun, Feb 1, 2009 at 8:24 PM, Daniel Jacobowitz <drow@false.org> wrote:
> On Sun, Feb 01, 2009 at 03:38:04PM -0800, Doug Evans wrote:
>> I haven't looked into siginfo, but can gdb look at the insn? [akin to
>> displaced stepping handling]
>
> I suppose, but I don't really see a point.

Apologies, it's not clear what point you're referring to.

I guess the issue is whether int3's in programs are supported by gdb,
and by supported I mean users can rely on gdb flagging a SIGTRAP when
they're executed. As you say, there are people who take advantage of
this for hardwired breakpoints.

There are various situations where gdb itself will singlestep code
(e.g., "step", "next", s/w watchpoints). Can users expect to see the
SIGTRAP in these situations (and all others)? And if the program is
being run by a script, can the script expect to see the SIGTRAP in all
cases?