Torsten Foertsch (torsten.foe...@gmx.net)

Hi,

where can I read more about perl IO? Are there API docs that explain what can
be used and what should better be avoided in external modules?

The reason for the question is this, why are there 2 FPs in an IO? There is an
IFP and an OFP, why? Can I open a file by IoIFP(io)=PerlIO_fdopen(1, "w")? Is
this sufficient?

Thanks,
Torsten

Actually SvFAKE_on(sv) leads to

Assertion he->shared_he_he.hent_hek == hek failed: file "hv.c", line
2257.

Torsten

I thought so but I haven't found any documentation about that flag. Is
there any? BTW, is SVf_FAKE available in 5.8.8?

Torsten

To answer myself, I think this does the trick:

      sv=newSV(0);
      SvUPGRADE(sv, SVt_PV);
      SvPOK_only(sv);
      SvPV_set(sv, pointer);
      SvLEN_set(sv, 0);
      SvCUR_set(sv, length);
      SvREADONLY_on(sv);

It depends on the fact that Safefree is not called if SvLEN(sv)==0. Can
I rely on that in the future?

Torsten

Hi,

perhaps this is not the right list but I know the knowledge is here. So,
please be lenient.

I have a bunch of C-strings with or without a trailing \0. I want to
make them available in Perl as read-only variables. When the perl SV is
destroyed the string must not be freed obviously.

Do I need to make those variables magic? Or is there a simpler way?

If I need magic, do I need to implement all of the 8 MGVTBL members?
What if some of them are NULL?

I think I need only an svt_free function that does:

SvPVX(var) = NULL;
SvCUR(var) = 0;

Is this correct?

I have read somewhere that perl strings do not need the trailing \0
byte. But for some reasons it is normally allocated. Why? Is it
necessary? What can happen if there is no trailing \0?

Thanks,
Torsten