Nick Ing-Simmons <[EMAIL PROTECTED]> writes:
> To let Tk list know a major gotcha blocking Tk release is fixed.
> Thanks to Steve Lide for the guest account on his G5 machine
> to track this!
>
> To let perl-xs list know even I am human and do dumb things ...
>
> void
> WidgetMethod(widget,name,...)
> SV * widget;
> SV * name;
> CODE:
> {
> Lang_CmdInfo *info = WindowCommand(widget, NULL, 1);
> XSRETURN(Call_Tk(info, items, &ST(0)));
> }
>
> Looks neat and tidy - but is fatally flawed.
> XSRETURN macro is basically
>
> THE_PERL_STACK_POINTER += Something.
>
> On Steve's G5 - that gets compiled as
> Get PERL_STACK_POINTER
> call function which returns value
> add
> Set PERL_STACK_POINTER
>
> The snag is that when function which returns value is a
> perl callback it can move the stack.
> So after above the stack pointer is pointing into an old stack
> which has now been free'd and re-used => CORE.
>
> Changing it to:
>
> void
> WidgetMethod(widget,name,...)
> SV * widget;
> SV * name;
> CODE:
> {
> Lang_CmdInfo *info = WindowCommand(widget, NULL, 1);
> IV count = Call_Tk(info, items, &ST(0));
> XSRETURN(count);
> }
>
> Fixes the problem.
Is this worth a note in perlapi.pod?
Regards,
Slaven
--
Slaven Rezic - [EMAIL PROTECTED]
Berlin Perl Mongers - http://berlin.pm.org
