regexp_count() Not Matching All [:punct:] Characters

[TheZenbudda]

It was my understanding that specifying [[unct:]] as a regexp would find all special characters: ! ' # S % & ' ( ) * + , - . / : ; < = > ? @ [ / ] ^ _ { | } ~

However, when I run this code, it shows it's not a match:

with tmp as (
select 
    '~' as string
from sysibm.sysdummy1
)
select
    tmp.string
    , regexp_count(tmp.string,'[[:punct:]]') as punctmatchcount
    , regexp_count(tmp.string,'[^[:punct:]]') as punctunmatchcount

from tmp
; 

Am I missing something?

[TheZenbudda]

Here is a list of the characters that do qualify as punct: !@#%&*()_-{}[]\:;,.?/