Hi. Content = "abcab", expression = "a{1, 2}b?c" + "a{1, 2}b?c" (doubled pattern). I think the expression can be simplified even more. As you can see, there's only partial match, and boost::regex_search(content, m, expression, boost::match_partial); detects it. But boost::regex_search(content, m, expression, boost::match_partial | boost::match_any); doesn't detect it. I expected that boost::match_any doesn't affect the main result (found or not), but just can return different sub-results (where and what found). Can you please explain where I'm wrong? Environment: VC 8.0, boost 1.33.1. Best regards, Andriy Tylychko, mailto:telya@mail.ru telya@mail.ru