Hi Using grep -P for boundary matches yields incorrect results with non-ASCII letters:
$ echo 'Öst' | grep -P '\bs' Öst The output should be nothing in this case, and the culprit seems to be this line in pcresearch.c: flags |= PCRE2_UTF; If the PCRE2_UCP flag is added according to this, the program behaves correctly: flags |= PCRE2_UTF|PCRE2_UCP; The pcre2grep test program in the pcre2 has the same problem, and I filed an issue there too: https://github.com/PCRE2Project/pcre2/issues/185 A Twitter discussion with more examples: https://twitter.com/gro_tsen/status/1610972356972875777 Kind regards -- Karl Pettersson Uppsala, Sverige/Sweden https://static-dust.klpn.se/