C++类成员能当做变量类型吗？

弱逼问题：S::*xmeth是个啥？ S是个类吧，xmeth是类的一个成员？成员能当做变量类型吗？
贴上相关代码
全选复制放进笔记template void

rpcs::reg(unsigned int proc, S*sob, int (S::*meth)(const A1 a1, const A2 a2, 
            R & r))
{
    class h1 : public handler {
        private:
            S * sob;
            int (S::*meth)(const A1 a1, const A2 a2, R & r);
        public:
            h1(S *xsob, int (S::*xmeth)(const A1 a1, const A2 a2, R & r))
                : sob(xsob), meth(xmeth) { }
            int fn(unmarshall &args, marshall &ret) {
                A1 a1;
                A2 a2;
                R r;
                args >> a1;
                args >> a2;
                if(!args.okdone())
                    return rpc_const::unmarshal_args_failure;
                int b = (sob->*meth)(a1, a2, r);
                ret << r;
                return b;
            }
    };
    reg1(proc, new h1(sob, meth));
}