DB<15> print join(" ", map { sprintf "%#02x", $_ } unpack("C*",pack("D",$a))), "\n";
0x41 0xb2 0x34 0x56 0x78 00 00 00

  DB<16> print join(" ", map { sprintf "%#02x", $_ } unpack("C*",pack("D*",$a))), "\n";
0x41 0xb2 0x34 0x56 0x78 00 00 00

  DB<17> print join(" ", map { sprintf "%#02x", $_ } unpack("C*",pack("d*",$a))), "\n";
0x41 0xb2 0x34 0x56 0x78 00 00 00

  DB<18> print join(" ", map { sprintf "%#02x", $_ } unpack("C*",pack("d",$a))), "\n"; 
0x41 0xb2 0x34 0x56 0x78 00 00 00