c++ wchar拼接

WCHAR* concatWcharStr(const WCHAR* str1, const WCHAR* str2) {
    size_t len1 = wcslen(str1) * 2;
    size_t len2 = wcslen(str2) * 2;
    size_t len3 = len1 + len2;
    char* address = (char*)malloc(len3 + 2);
    for (size_t i = 0; i < len1; i++)
        address[i] = ((char*)str1)[i];
    for (size_t i = len1; i < len3; i++)
        address[i] = ((char*)str2)[i];

    address[len3] = '\0';
    address[len3 + 1] = '\0';

    return (WCHAR*)address;
}