Re^8: SvUV vs SvIV for pointers in SVs, typemap

in reply to Re^7: SvUV vs SvIV for pointers in SVs, typemap
in thread SvUV vs SvIV for pointers in SVs, typemap

#!/usr/bin/perl -w
use Devel::Peek;
$ptrUV = unpack('J',pack('P[12]',"Hello World"));
$ptrIV = unpack('j',pack('P[12]',"Hello World"));
print Dump($ptrUV);
print Dump($ptrIV);
$ptrUV += 2**31;
print Dump($ptrUV);
[download]

SV = IV(0x182a260) at 0x182a264
  REFCNT = 1
  FLAGS = (IOK,pIOK)
  IV = 28545556
SV = IV(0x182a3e0) at 0x182a3e4
  REFCNT = 1
  FLAGS = (IOK,pIOK)
  IV = 26107564
SV = IV(0x182a260) at 0x182a264
  REFCNT = 1
  FLAGS = (IOK,pIOK,IsUV)
  UV = 2176029204
[download]

Perl keeps all unsigneds as IVs until they are greater than IV_MAX (~ +2 billion), then it uses the UV flag/UV mode. [sv.c#l1620 in perl.git] But, if the pointer is larger than 2 billion, and the user manipulates the pointer, for struct offsets for example, before passing it to unpack, or passes the scalar with the pointer inside it to an XSUB that takes a pointer (bad XSUB design right?)

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