I've done some further tests and the following fragment :- $a = hex("FFFFFF00"); printf "%X %X\n", $a, ~$a; $a = 0xFFFFFF00; printf "%X %X\n", $a, ~$a; returns FFFFFF00 FF ! Correct FFFFFF00 7FFFFFFF ! Wrong So I at least have a workaround with hex() to use, even if 0xffffff00 does not work as a C programmer might expect it to! (This is macPerl 5.0.7 now) End of story. -------------------------------------------------------------------------------- Roger Hill aka roger@aeg-post.demon.co.uk Call this a sig....:-?