"C++ Builder XE8" can I use the "UnicodeString", but want to use the "std::wstring".
So, there is a need to convert from UnicodeString to "std::wstring".
It is useful when using the reason is, "boost"
Using the w_str() if it is stored in the "std::wstring".
Conversely, if you are housed in a "UnicodeString" is to use the "xx.sprintf(xx.c_str ())".
For other string, it is written in Yamamotosan blog article.