Tassilo Parseval <[EMAIL PROTECTED]> writes:
>On Mon, Jan 19, 2004 at 02:46:46AM -0800 Gisle Aas wrote:
>> Tassilo von Parseval <[EMAIL PROTECTED]> writes:
>>
>> > I was experimenting with something like
>> >
>> > PerlIO *io;
>> > char mode[8];
>> > PerlIO_intmode2str(O_RDONLY|O_NONBLOCK, mode, NULL);
>> > io = PerlIO_fdopen(self->fd, mode);
>> >
>> > but I can't even figure out whether this works because I don't know how
>> > to turn a PerlIO* thingy into an SV. Actually, I don't know what to do
>> > with this PerlIO stuff at all. According to perlapio.pod, this is the
>> > thing to work with when doing I/O from XS. But there is not a single
>> > indication anywhere how to turn an SV into a PerlIO and vice versa.
>>
>> The standard perl typemap have this OUTPUT entry for PerlIO:
>>
>> T_INOUT
>> {
>> GV *gv = newGVgen("$Package");
>> if ( do_open(gv, "+<&", 3, FALSE, 0, 0, $var) )
>> sv_setsv($arg, sv_bless(newRV((SV*)gv), gv_stashpv("$Package",1)));
>> else
>> $arg = &PL_sv_undef;
>> }
>
>Thank you, this helps. But, hmmh, unfortunately it doesn't yet solve all
>my problems. My first attempt:
>
> PerlIO*
> fh (self)
> CDROM *self;
> PREINIT:
> char mode[8];
> PerlIO *io;
> CODE:
> {
> PerlIO_intmode2str(O_RDONLY|O_NONBLOCK, mode, NULL);
The O_NONBLOCK _may_ be confusing it.
And as thing is already open doesn't contribute much.
> io = PerlIO_fdopen(self->fd, mode);
> RETVAL = io;
> }
> OUTPUT:
> RETVAL
>
>This returns me something that is blessed into my class, but it is
>apparently not a filehandle.
Looking at C code out of xsubpp would help us here.
These typemaps are a little fragile - for example
if you are using perl5.6 things are rather different.
If the PerlIO_fdopen() has failed it isn't clear typemap
will always return undef
>When trying to do
>
> my $fh = $cd->fh;
> ioctl($fh, CDROMEJECT, 0);
>
>perl will complain about $fh not being a GLOB-reference.
Which would be the case for an undef - i.e. a failed
fdopen().
>
>I now do it this way and this seems to work:
>
> void
> fh (self)
> CDROM *self;
> PREINIT:
> char mode[8];
> GV *gv;
> STLLEN modlen;
> CODE:
> {
> modlen = sprintf(mode, "<&%i", self->fd);
> gv = newGVgen("Device::CDROM");
> do_openn(gv, mode, modlen, FALSE, O_RDONLY|O_NONBLOCK, 0, Nullfp,
> (SV**)NULL, 0);
> sv_setsv(ST(0), sv_2mortal(newRV((SV*)gv)));
> XSRETURN(1);
> }
>
>I am not extremely happy with this since it looks like cheating. Also I
>am not sure whether it is legitimate to use do_openn() since it is not
>in the public API (although this typemap you mentioned does something
>similar).
The typemap uses an icky legacy interface which isn't really
in the public API either.
It would be good to _design_ an XS/PerlIO API - what do you
want to be able to do?
>
>Anyway, even though this appears to work, I don't understand PerlIO at
>all.
>
>Tassilo
