$s = '20 ducks';;
Dump $s;;
SV = PV(0x18aec0) at 0xa5b48
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x40cad18 "20 ducks"\0
  CUR = 8
  LEN = 16

[download]

Length = 16. Now use it in a numeric constant. 

$s += 1;;
Argument "20 ducks" isn't numeric in addition (+) at (eval 13) line 1,
+ <STDIN> line 4.

Dump $s;;
SV = PVNV(0x40b1eb8) at 0xa5b48
  REFCNT = 1
  FLAGS = (NOK,pNOK)
  IV = 20
  NV = 21
  PV = 0x40cad18 "20 ducks"\0
  CUR = 8
  LEN = 16

[download]

Hm. Length still 16, but we gained an IV = 20 and an NV = 21; so we gained 12 or 16 bytes.

Oh, and the PV no longer reflects the value of the scalar, so when you use it in a string context, a conversion has to happen! 

print $s;;
21

Dump $s;;
SV = PVNV(0x40b1eb8) at 0xa5b48
  REFCNT = 1
  FLAGS = (NOK,POK,pNOK,pPOK)
  IV = 20
  NV = 21
  PV = 0x40d3068 "21"\0
  CUR = 2
  LEN = 40

[download]

Which modifies the PV and oops, it grew to 40 bytes in the process.

And I don't care how you try to weasel out of it, the evidence is right there for those that care to look. So don't bother.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re^3: Question on SV internals by BrowserUk
in thread Question on SV internals by John M. Dlugosz

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