$e = sprintf( '%s', undef );;
Use of uninitialized value in sprintf at (eval 28) line 1, <STDIN> line 20.

##</code><code>##


eval{ 
    local $SIG{__WARN__} = sub{ 
        printf STDERR "Warning detected: %s", $_[0]; 
    }; 
    $e = sprintf( '%s', undef ); 
};;
Warning detected: Use of uninitialized value in sprintf at (eval 29) line 1, <STDIN> line 21.