c++ char* str_to_char_array string转char*

char* str_to_char_array(const std::string& str) {
std::unique_ptr<char> _char_array(new char[str.length() + 1]);
char* char_array = _char_array.release();
std::copy_n(str.c_str(), str.length() + 1, char_array);
return char_array;
}