There's no such thing as a SvUV. A ref can be in practically any type of SV (at least SvIV, SvNV, SvPV, SvPVIV, SvPVNV).

>perl -MDevel::Peek -e"my $x = {}; Dump($x);"
SV = IV(0x3269b8) at 0x3269c0
  REFCNT = 1
  FLAGS = (PADMY,ROK)
  ...

>perl -MDevel::Peek -e"my $x = 'abc'; $x = {}; Dump($x);"
SV = PV(0x33abe0) at 0x2a69d0
  REFCNT = 1
  FLAGS = (PADMY,ROK)
  ...

>perl -MDevel::Peek -e"my $x = 'abc'; $x = 123; $x = {}; Dump($x);"
SV = PVIV(0x28da78) at 0x2a6a60
  REFCNT = 1
  FLAGS = (PADMY,ROK)
  ...
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A reference is indicated by the ROK flag. The pointers of references are neither IV nor UV. The pointers are returned as SV* as they should. The actual pointer is located in the same location as an IV's number or UV's number, so ROK && IOK is impossible.

illguts

Update: It appears possible to have an SV that is both ROK and IOK. It would have to be hand-crafted; Perl never constructs one. No idea if it's safe to construct one.

I got sidetracked in the parent post. The OP asks about C pointers stored in an SV as numbers, not as references.

The answer is quite simple: It doesn't matter whether it's stored as an IV or as an UV since the value is casted to the correct pointer type before anything ever sees it as a number.

By the way, that code will work whether it's stored as an IV or as an UV.

shouldn't pointers be SvUV not SvIV?

On 32-bit OSs they certainly should be. Whilst out-of-the-box, 32-bit OSs only provide user space programs with access to the lower 2GB of ram; most if not all of them can push that upto 3GB with the appropriate build or start-up options.

And at that point using signed math on pointers could render incorrect results.

If you cast the pointer to some int type, pointer arithmetic will be wrong whether it's signed or not.

use Inline C => <<'__EOI__';

int test() {
   SV* sv = &PL_sv_undef;
   printf("%p\n", sv+2);
   printf("%p\n", ((IV)sv)+2);
   printf("%p\n", ((UV)sv)+2);
}

__EOI__

test();
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0x746310
0x7462e2
0x7462e2
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If you cast the pointer to some int type,

And if you clean your windscreen with a hammer, you'll not like the results either.

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