On Sat, Jan 10, 2004 at 04:48:17PM +0000 Nick Ing-Simmons wrote:
> Tassilo Parseval <[EMAIL PROTECTED]> writes:
> >Hi,
> >
> >two little questions this time.
> >
> >1) When I return multiple values from an XSUB by doing a
> >
> > ST(0) = sv_newmortal(...);
> > ST(1) = sv_newmortal(...);
> > XSRETURN(2);
> >
> >do I have to do a prior EXTEND(SP, 2)? Currently I am not doing it and
> >it seems to work fine.
>
> It depends how many args you are passed. If you have at least two args
> then at least two slots exist.
That goes along with what Nick (the other one;-) says.
> But as EXTEND is a macro and cheep if it doesn't need to do anything
> you may as well put it in.
I didn't know that EXTEND only extends on demand. Good to know.
> >2) For some parameter parsing, I'd like to get rid of a few warnings
> >that happen when I do a 'SvIV(ST(n))' and ST(n) is not SvIOK but rather
> >a string or so.
>
> SvIV() will upgrade a string that looks like a number
> (and indeed there is a function looks_like_a_number() you can use.)
The code in question is rather repetitive and I'd like to keep it as
short as 'int var = SvIV(ST(n))'.
> >I didn't find an interface to the warnings and so poked
> >around a little in warnings.h. Right now I'm doing it this way:
> >
> > CODE:
> > {
> > SV *oldwarn = PL_curcops->cop_warnings;
> > PL_curcops->cop_warnings = pWARN_NONE;
> > ...
> > PL_curcops->cop_warnings = oldwarn;
> > XSRETURN_YES;
> > }
> >
> >Is there a clean and commonly accepted way of doing it?
>
> I don't know - the above is exactly what Tk does in the one spot
> it bothers to do anything.
> I tend to code defensively so warnings go away.
Ah, good. If it's good enough for Tk, then it's good enough for me as
well.
> >And if not, is
> >the above reliable?
>
> The risk is if what you show as '...' can croak() - then perhaps something to
> restore the SV would be appropriate.
That fortunately can't happen in this particular case. But om the
future, I might need something more generic, so...
> As this is an SV there is an save_item() to do the job (I think - I
> always have to read scope.c for the save_xxx() stuff).
A
save_item(PL_curcops->cop_warnings);
PL_curcops->cop_warnings = pPWARN_NONE;
would automatically restore PL_curcops->cop_warnings upon leaving the
XSUB? That would be pretty cool.
Tassilo
--
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$_=reverse,s+(?<=sub).+q#q!'"qq.\t$&."'!#+sexisexiixesixeseg;y~\n~~dddd;eval
