isync has asked for the wisdom of the Perl Monks concerning the following question:

Am I missing something. C (Byte), and n (Short) work as expected, but bigger (Long) integers give me 5 (00 00 00 05 instead of FF FF FF FF?
A reverse unpack("N","\xFFFFFFFF") works as well... 
#!perl
use Data::HexDump;
my $bin = pack("N",42949672965);
print HexDump($bin);

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Replies are listed 'Best First'.
Re: Why is pack("N",42949672965) giving me 00 00 00 05
by BrowserUk (Patriarch) on Feb 08, 2015 at 22:30 UTC

    Because template 'N' is for a unsigned 32-bit value, but 42949672965 requires 36-bits: 0xA_0000_0005; so the high 4-bits are discarded leaving: 0x0000_0005.

    If your Perl is capable, use 'Q' instead for integers > 32-bit.

    With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
    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". I'm with torvalds on this
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Re: Why is pack("N",42949672965) giving me 00 00 00 05
by Eily (Monsignor) on Feb 08, 2015 at 22:29 UTC

    You wrote 42949672965 instead of 4294967295

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Re: Why is pack("N",42949672965) giving me 00 00 00 05
by LanX (Saint) on Feb 08, 2015 at 22:33 UTC
    > Am I missing something.

    typo! :)

      DB<122> pack ('N',2**32-1)
 => "\xFF\xFF\xFF\xFF"

  DB<123> 2**32-1
 => 4294967295

  DB<124> 2**32-1 - 42949672965
 => -38654705670

    [download]

    Cheers Rolf

    PS: Je suis Charlie!

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[d/l]
Re: Why is pack("N",42949672965) giving me 00 00 00 05
by isync (Hermit) on Feb 09, 2015 at 00:32 UTC
    Arg! Sure sign of too many hours on the keyboard... Fellow monks, thank you very much everyone!
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      You know you can use 0xFFFFFFFF, right?
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[d/l]

        ... or even 0xFFFF_FFFF or 4_294_967_295 for that matter.

        Give a man a fish:  <%-(-(-(-<

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[d/l]
        @ ikegami: yes, knew that.
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