in reply to reading packed unsigned long long

It was brought to my attention that despite your use of singular, the hex string should contain 4 numbers. That makes more sense, but your input is still messed up.

"unsigned long long" is not very descriptive. Even saying "C's unsigned long long" is not very descriptive. That simply means they are at least 64-bit and says nothing of byte order.

It seems you want to unpack unsigned 64-bit integers in native or network byte order. 

my @vals = unpack('Q*',  pack('H*', "000...."));  # Native byte order
my @vals = unpack('Q>*', pack('H*', "000...."));  # Network byte order

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">" requires Perl 5.10
"Q" requires a build of Perl that can actually hold 64-bit integers.

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Re^2: reading packed unsigned long long
by Spooky (Beadle) on Jul 15, 2009 at 14:24 UTC
    I found out a little bit more about that HEX representation: ..turns out that the last two fields are six bytes and eight bytes (00000000004a/000000000000004a) equalling a decimal 74. I guess I really need to know the correct combination of format characters (e.g., 'NNCNN' - I've tried the "Q" option which my system rejects)....
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      Rejected how? "Invalid type 'Q' in unpack"? Note the comment at the bottom of my previous post. Your Perl can't handle 64-bit numbers because your processor can't handle them natively. You could build a Perl that supports 64-bit numbers (even if your processor doesn't handle them natively), or you could use Math::BigInt to hold such a big number. I'll even code the solution if you tell me which byte ordering you want to use.

      turns out that the last two fields are six bytes and eight bytes

      There's no unpack specifier for reading 6-byte ints. j and J might be 6-bytes on your machine, but I'd be surprised. Nobody uses 6-byte ints. That's part of why I said your data is messed up. 

      You expect         To get that        What you have
----------------   ----------------   ----------------
0                  0000000000000000
5967*              000000000000174f   000000000000174f
74                 000000000000004a     0100000000004a
74                 000000000000004a   000000000000004a

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      * — You actually said 5976. I presume that's a typo.

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        Hi - ..I get "Invalid type in unpack: 'Q'" ..you're right, "J" & "j" don't cut it either... ...thanks for the offer, what's the standard byte order? I also want to look into "Math::BigInt" - I've never heard of this: is it a library of Perl functions?
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