Am I checking for undef in the wrong way?

[Erland Sommarskog]

I have an issue with an XS module of mine. I lean towards that it is a
bug in threads::shared, but maybe I am doing something wrong?

To show the issue, I have this silly XS routine:

   void
   arraytest(arrayref)
         SV * arrayref
   CODE:
   {
     AV *  av = (AV *) SvRV(arrayref);
     SV ** svp = av_fetch(av, 0, 0);
     SV *  sv  = *svp;
   
     warn ("SvOK = %d\n", SvOK(sv));
     warn ("SvIV = %d\n", SvIV(sv));
     warn ("SvOK = %d\n", SvOK(sv));
   }

The main script runs:

   my $arrayref = [5678];
   arraytest($arrayref);
   my $shared_arrayref : shared = shared_clone($arrayref);
   arraytest($shared_arrayref);

The output is:

   SvOK = 4352
   SvIV = 5678
   SvOK = 4352
   SvOK = 0
   SvIV = 5678
   SvOK = 4096

That is, when I send in a regular array reference, results are as
expected. But when the reference is a shared object, SvOK first 
returns 0. When I retrieve the value with SvIV I get the correct
value nevertheless, and next time SvOK returns a true value!

Am I doing somethinug wrong? Or should I file a bug for threads::shared?

If it is a bug, any suggestion for a workaround? In the real module, the
value can be of any type, so SvIV does not seem like a good idea.

This happens on Win32 with ActivePerl builds 1005. I attach my test
module and test script (which also shows the same thing happens with a
hash reference.)



-- 
Erland Sommarskog, Stockholm, esq...@sommarskog.se

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