in reply to Stumped by a pack/unpack problem

what about reverse pack("f", 440.0)

The reason for the difference on MAC and PC is that the real numbers are in the native machine format only. For more information see perldoc -f pack and perldoc perlport.

sorry, my first idea works just with unpack("H*", reverse pack("f", 440.0)) vs unpack("H*", pack("f", 440.0))

By the way on my PC pack("f", 440.0) is 00 00 DC 43.
and pack("N", unpack("l", pack("f", 440.0))) just returns 43 dc 00 00

And the fastest solution would be a XS implementation.