I'm not sure why you would want a "1 but false" return value. The "0 but true" value is perl sugar for those cases where the underlying library returned 0 for true values and -1 for errors (ioct, fcntl, shmctl, etc). About the only place I've seen 1 be a "false" value is not for API calls but for exit statuses and then there's normally a range of positive exit values that indicate what the failure is (and 0 would be normal exit).

-derby