I would guess that your packed string '$p' has either a single quote "'" in it or an escape or $ or @ at the end that eats the closing single quote

I should add that there's nothing special about the given NV value of 2.4.
The behaviour I'm seeing is happening for all NV values that I've tested.

To get a dump of $s: 
# test.pl

use warnings;
use Devel::Peek;

$template = 'D<';
$nv = 2.4;
$p = pack $template, $nv;
$s = "'$p'";

Dump $s;

system $^X, '-wle', "print unpack('H*', $s);";

[download]
That outputs the following (which does, at least, contain an "@"): 
C:\_32\pscrpt>perl test.pl
SV = PV(0x4bcf98) at 0x571248
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x4b7e88 "'\232\231\231\231\231\231\231\231\0@\0\0\0\0\0\0'"\0
  CUR = 18
  LEN = 20
Can't find string terminator "'" anywhere before EOF at -e line 1.

[download]
But if I change the value of $nv to 2.4e100, I get: 
C:\_32\pscrpt>perl test.pl
SV = PV(0x3ecf98) at 0x383348
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x3e7e88 "'\vL\177v\257zb\206\264>\0\0\0\0\0\0'"\0
  CUR = 18
  LEN = 20
Can't find string terminator "'" anywhere before EOF at -e line 1.

[download]
Interestingly, changing the value to 3.1e-100 results in a different warning: 
C:\_32\pscrpt>perl test.pl
SV = PV(0x26cf98) at 0x5311f8
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x267e88 "'9\302\271\243\"\211\224\255\264>\0\0\0\0\0\0'"\0
  CUR = 18
  LEN = 20
Use of uninitialized value $_ in print at -e line 1.

[download]
Perhaps something to do with the internal double quote.

For a value of 13.16e-100, I get: 
C:\_32\pscrpt>perl test.pl
SV = PV(0x38cf98) at 0x4c51b8
  REFCNT = 1
  FLAGS = (POK,pPOK)
  PV = 0x387e88 "'\245^,\356\266\0208\270\266>\0\0\0\0\0\0'"\0
  CUR = 18
  LEN = 20
Can't find string terminator "'" anywhere before EOF at -e line 1.

[download]
Is there some way to pass the string returned by pack() to that system command ?
I assume that it ought to be possible, and that I'm just doing something dumb.

Cheers,
Rob

In reply to Re^2: pack() returns an unusable string by syphilis
in thread pack() returns an unusable string by syphilis

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