1..10 --------------- (?^:ax(?!ba)) --------------- ok 1 - (0) axba => axba ok 2 - (1) axbb => -bb ok 3 - (2) axccaxdd => -cc-dd ok 4 - (1) axbaxcc => axb-cc not ok 5 - (1) axcaxcc => -c-cc # Failed test '(1) axcaxcc => -c-cc ' # at Y:\atp01082\data\data\Perl\test\regex_not.pl line 30. # got: 2 # expected: 1 --------------- (?^:ax[^b][^a]) --------------- ok 6 - (0) axba => axba not ok 7 - (1) axbb => axbb # Failed test '(1) axbb => axbb ' # at Y:\atp01082\data\data\Perl\test\regex_not.pl line 30. # got: # expected: 1 ok 8 - (2) axccaxdd => -- ok 9 - (1) axbaxcc => axb- ok 10 - (1) axcaxcc => axc- # Looks like you failed 2 tests of 10.