语法
class synchronized_pool_resource : public memory_resource {
synchronized_pool_resource(const pool_options& opts, memory_resource* upstream);
synchronized_pool_resource()
: synchronized_pool_resource(pool_options(), get_default_resource()) {}
explicit synchronized_pool_resource(memory_resource* upstream)
: synchronized_pool_resource(pool_options(), upstream) {}
explicit synchronized_pool_resource(const pool_options& opts)
: synchronized_pool_resource(opts, get_default_resource()) {}
synchronized_pool_resource(const synchronized_pool_resource&) = delete;
virtual ~synchronized_pool_resource();
synchronized_pool_resource&
operator=(const synchronized_pool_resource&) = delete;
void release();
memory_resource* upstream_resource() const;
pool_options options() const;
};