different result of regexp_instr than on Oracle

[Pavel Stehule]

Hi

I got an error report for regexp_instr in Orafce.

SELECT REGEXP_INSTR('ABC', 'A', 1, 1, 0, '', 1) AS SUBEXPR_1

Oracle returns 0, Postgres 1.

Because Orafce now share this functionality with Postgres, there should be
same problem

Is this behaviour expected?

Regards

Pavel