visual c++ - std::regex fatal error -


i'd think isn't bug in standard library, i'm running out of places look.

the statement std::regex(expression) expression std::string causes memory access fatal error.

expression declared statement:

std::string expression = std::string("^(") +     std::string("[\x09\x0a\x0d\x20-\x7e]|") + // ascii     std::string("[\xc2-\xdf][\x80-\xbf]|") + // non-overlong 2-byte     std::string("\xe0[\xa0-\xbf][\x80-\xbf]|") + // excluding overlong     std::string("[\xe1-\xec\xee\xef][\x80-\xbf]{2}|") + // straight 3-byte     std::string("\xed[\x80-\x9f][\x80-\xbf]|") + // excluding surrogates     std::string("\xf0[\x90-\xbf][\x80-\xbf]{2}|") + // planes 1-3     std::string("[\xf1-\xf3][\x80-\xbf]{3}|") + // planes 4-15     std::string("\xf4[\x80-\x8f][\x80-\xbf]{2}") + // plane 16     ")*$";

this regex taken http://www.w3.org/international/questions/qa-forms-utf-8 test whether byte sequence utf8.

is bug in library, or missing tiny?

compiled vs2015 c++, if happens make difference.

edit: forgot mention there 1 specific line in breaks code. std::string("[\xe1-\xec\xee\xef][\x80-\xbf]{2}|") + // straight 3-byte line breaks. comment out , works fine. line on it's own creates memory access error.

so, if use escapes in string literals, without using raw syntax,
have escape escapes.

example, new string: 

std::string expression = std::string("^(") +     std::string("[\\x09\\x0a\\x0d\\x20-\\x7e]|") + // ascii     std::string("[\\xc2-\\xdf][\\x80-\\xbf]|") + // non-overlong 2-byte     std::string("\\xe0[\\xa0-\\xbf][\\x80-\\xbf]|") + // excluding overlong     std::string("[\\xe1-\\xec\\xee\\xef][\\x80-\\xbf]{2}|") + // straight 3-byte     std::string("\\xed[\\x80-\\x9f][\\x80-\\xbf]|") + // excluding surrogates     std::string("\\xf0[\\x90-\\xbf][\\x80-\\xbf]{2}|") + // planes 1-3     std::string("[\\xf1-\\xf3][\\x80-\\xbf]{3}|") + // planes 4-15     std::string("\\xf4[\\x80-\\x8f][\\x80-\\xbf]{2}") + // plane 16     ")*$";

when don't escape them, compiler tries interpret a
special character. in case interpreting hex binary characters.

and, while regex engine gets right character,
better pass hex engine can see character
might break (if does).


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