Regular expression - PCRE (PHP) - word boundary (\b) and accent characters

Question

Why does the letter é count as a word boundary matching \\b in the following example?

Pattern: /\\b(cum)\\b/i

Text:

Answer 1

It will work, when you add the u modifier to your regex

/\b(cum)\b/iu

Answer 2

To deal with unicode, replace \b with

/(?<=^|\PL)(cum)(?=\PL|$)/i