Thanks! OK, got it and tried it. The documentation is a bit sparse, but using String::CRC gives rise to a program like so:

use strict;
use warnings;

use String::CRC;

my $message = $ARGV[0];

my $crc16 = crc($message);
print "CRC16 in decimal: $crc16\n";
print "CRC16 in hex:\n  ", unpack('H*', pack('S', $crc16)), "\n";
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Running the program gives this output:

cradcliff% ./crc16-modular.pl foo
CRC16 in decimal: 1736882148
CRC16 in hex:
  b7e4
cradcliff% ./crc16-modular.pl foobar
CRC16 in decimal: 3375757715
CRC16 in hex:
  f993
cradcliff% ./crc16-modular.pl foobaz
CRC16 in decimal: 3375757723
CRC16 in hex:
  f99b
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More simply:

'foo'    => 0xb7e4
'foobar' => 0xf993
'foobaz' => 0xf99b

Can anyone verify that these are correct values for a CRC-16 checksum, assuming the conditions I specified earlier? Alternately, can anyone supply sample string-checksum pairs I can use to test this program?

Thanks, ~c

Try crc($message,16); because the default is 32 (like the pod says).

MJD says you can't just make shit up and expect the computer to know what you mean, retardo! I run a Win32 PPM repository for perl 5.6x+5.8x. I take requests. ** The Third rule of perl club is a statement of fact: pod is sexy.

Yes, I forgot to add that. Unfortunately, even with the change, the result is:

cradcliff% ./crc16-modular.pl 123456789
CRC16 in decimal: 4535
CRC16 in hex:
  11b7

...which doesn't match the 0xBB3D result provided by the on-line calculator. I'm guessing that String::CRC doesn't use the CRC-16 polynomial or some other CRC-16-specific setting.

I'll check my other algorithm against the on-line calculator. If anyone has algorithmic hints, please post them.