That's terrific, thanks.

That uses the first idea: unpack as two L's.

It seems your design goal was portability, since you automatically detect the endian.

I see that you try to unpack "Q" first (in the signed form, you should be using "q"). I like that idea, but I think I'll swap out the whole sub so it only tries once when it decides it can't do that. In yours, you'll confuse a valid 0 integer with failure.

I noticed you wrote 1+~0 for 0x100000000, and my first impression was that this was also for portability. But, I think it's nonportable now, and that's just clearer than writing it out in decimal (the hex form overflows Perl's parser and is not allowed). But, unpack "L" is specifically 32-bit fields and not necessarily the native size, and nowhere does it say what size bit operators operate on, but I think this is the definition of "native size".

So, you are assuming that the native size is 32 bits if quadword support is disabled. I think I'll use 2**32 for clarity, and trust the optomizer to fold the constant arithmetic down.

—John

update: I didn't notice the extra ;1; at the end of the eval block. Cute. But easy to miss.