How to use Unicode range in C++ regex

I have to use unicode range in a regex in C++. Basically what I need is to have a regex to accept all valid unicode characters..I just tried with the test expression and facing some issues with it.

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std::regex reg("^[\u0080-\uDB7Fa-z0-9!#$%&'*+/=?^_`{|}~-]+$");

Is the issue is with \u?