Re: Perl sha256 question

Tip #2 from the Basic debugging checklist: Display the contents of variables using print or warn:

use strict;
use warnings;
use Digest::SHA qw( sha256_hex );

my $h = 5472151337331275;
print "\$h = >$h<\n\n";
print sha256_hex($h), "\n";
[download]

On Perl v5.24.0, which is 64-bit:

17:40 >perl 1639_SoPW.pl
$h = >5472151337331275<

b5951ee4a7cbfdc9df6b1b74de2d1ba865de40796c756cebe88a806c5a7b9e60

17:40 >
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— which is as expected. But on Perl v5.14.4, which is 32-bit:

17:33 >perl 1639_SoPW.pl
$h = >5.47215133733128e+015<

32838cef9e4571b4fa9a5297e265cf860a31774de3ca339878d87238af604a45

17:34 >
[download]

As Anonymous Monk says, the fix is to turn the argument from a number into a string.

Hope that helps,

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

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Re^2: Perl sha256 question
by Anonymous Monk on May 24, 2016 at 01:49 UTC

Thank you so much :)

On the same machine and Perl version, when I set the number to a variable, it works:

use Digest::SHA qw(sha256_hex);

my $num = 5472151337331275;
print sha256_hex($num);
# b5951ee4a7cbfdc9df6b1b74de2d1ba865de40796c756cebe88a806c5a7b9e60
[download]

What difference does setting it to a variable make?

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[d/l]

Re^3: Perl sha256 question

by Athanasius (Archbishop) on May 24, 2016 at 02:48 UTC

It looks as though the assignment is performing a stringification. I haven’t been able to replicate this behaviour. What is your platform, and what is the output of perl -V?

Athanasius <°(((>< contra mundum Iustus alius egestas vitae, eros Piratica,

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[d/l]

Re^4: Perl sha256 question

by Anonymous Monk on May 24, 2016 at 03:13 UTC

Ah sorry my bad.

The sha256 output of 5489612208355686 when set to a variable is

"7b74ee85ff18d48641ab219377ad40f3331f242afd94ebb33ddd1e5d61d5b6de",

not

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