John Maddock wrote:

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Is it possible to define a traits class for regex that supports multibyte strings? I am intending to do so, but I'm unsure that it is possible because there are several required functions that take a parameter of type char_type, which wouldn't really hold a complete character.

I suspect that the answer is "no", can you not use wchar_t, and if necessary convert your multi-byte sequence to wchar_t "atoms" on- the-fly using iterator adapters?

I'll give it a try.