#!perl

for $invalue (qw/ 1 -10 abc /) {

    eval{ local $SIG{__WARN__} = sub { die @_ };
          local $^W = 1; () = $invalue + 0 };   ### Is Number?
    if ( $@ ) {
        print "$invalue is *not* a Number; Details: $@\n";
    } else {
        print "$invalue appears to be a number.\n";
    }

}