sprint a 64-bit number

Question

I want to print a 64-bit number into an other variable.

#!/bin/perl

use strict;
use bigint;

my $str         = "";
my $long_number = -1;

$str = sprintf("%016X", $long_number);

But when I print $str I see 00000000ffffffff.

It's like Perl considers my $long_number to be a 32-bit number.

I checked my Perl version. It looks correct :

perl --version

This is perl, v5.8.4 built for sun4-solaris-64int (with 37 registered patches, see perl -V for more detail

Does anyone know where my problem comes from ?

See: https://stackoverflow.com/questions/26168746/how-can-i-check-whether-my-perl-installation-is-32-or-64-bit — martin clayton, Jun 29 '17 at 07:58

martin clayton · Answer 1 · 2017-06-29T08:04:21.243

2

Although you're running on 64-bit Solaris, likely you have a 32-bit int Perl.

You could run perl -V (uppercase V) and check for compile-time options:

Characteristics of this binary (from libperl):
  Compile-time options: PERL_MALLOC_WRAP PERL_USE_SAFE_PUTENV
                        *USE_64_BIT_INT* USE_LARGE_FILES USE_PERLIO

Or perl -V:ivsize; size 8 indicates 64-bit, 4 32-bit.

edited Jun 29 '17 at 08:04

answered Jun 29 '17 at 07:55

martin clayton

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I've for compile-time options : USE_64_BIT_INT USE_LARGE_FILES and ivsize='8'; – LnlB Jun 29 '17 at 09:41

ikegami · Answer 2 · 2017-06-30T03:45:08.823

2

Your Perl does indeed use 64-bit integers as hinted by perl -v. This is confirmed by perl -V:ivsize returning 8.

The problem relates to use bigint;. Using that causes your -1 to be replaced with Math::BigInt->new(-1), and the the numification of that object is what you're printing. I bet it's that object's numification returns the 32-bit representation of -1.

Removing use bigint; should do the trick.

edited Jun 30 '17 at 03:45

answered Jun 29 '17 at 17:16

ikegami

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sprint a 64-bit number

2 Answers2