regular expressions in Prolog

After a little investigation, I found this Prolog code to match regular
expressions:

    match_regex(Regex, String, Result) :-
         send(Regex, match, String),
         findall(W, (between(1,9, Z),
                 get(Regex, register_value, String, Z, name, W)),
             Result), !.
     
    amatchesregexb(Astring, Bregex, Result) :-
       use_module(library(pce)),
       setup_call_cleanup(new(Binternalregex, regex(Bregex)),
                   match_regex(Binternalregex, Astring, Result),
                   free(Binternalregex)).

 However, when I used it I got the following results:

    130 ?- amatchesregexb('ab12cd', '.*([0-9]+).*', Result).
    Result = ['2'].
     
    131 ?- amatchesregexb('ab12cd', '[^0-9]*([0-9]+).*', Result).
    Result = ['12'].
     
    132 ?-


*I expected the first example capture **([0-9]+) to cap**ture '12', but
it only captured '2'.*

I had to add [^0-9] infront of the numeric capture to successfully
capture both digits '12'.

I'm a Prolog newbie, and don'tunderstand the code that I copied.

Can anyone tell me what is wrong about it?
**

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