C#でC++で書いたコードを流用

int Hoge::func(String ^ str_)
{
    char *str = (char*)(void*)Marshal::StringToHGlobalAnsi(str_);

    //何か処理

    Marshal::FreeHGlobal((IntPtr)(void *)buf);

    return(0);
}

int Hoge::func2(String ^ str_, array^ obuf_)
{
    char *str = (char*)(void*)Marshal::StringToHGlobalAnsi(str_);
    pin_ptr p = &obuf_[0];
    char *obuf = reinterpret_cast((char *)(void *)p);

    //何か処理

    Marshal::FreeHGlobal((IntPtr)(void *)buf);

    return(0);
}