convert std::string to std::wstring

to_wstring.cpp

#include <cstdlib>
#include <cwchar>
#include <string>
#include <memory>

std::wstring to_wstring(const char* str) {
	std::unique_ptr<wchar_t[]> tmp = nullptr;
	size_t sz, len;
	len = mbstowcs(nullptr, str, 0);
	sz = len + 1;
	tmp.reset(new wchar_t[sz]);
	mbstowcs(tmp.get(), str, sz);
	return std::wstring(tmp.get());
}
std::wstring to_wstring(const std::string& str) {
	return to_wstring(str.c_str());
}