1/*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package libcore.io;
18
19import java.io.FileDescriptor;
20
21/**
22 * Corresponds to C's {@code struct pollfd} from
23 * <a href="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/poll.h.html">&lt;poll.h&gt;</a>
24 */
25public final class StructPollfd {
26    /** The file descriptor to poll. */
27    public FileDescriptor fd;
28
29    /**
30     * The events we're interested in. POLLIN corresponds to being in select(2)'s read fd set,
31     * POLLOUT to the write fd set.
32     */
33    public short events;
34
35    /** The events that actually happened. */
36    public short revents;
37
38    /**
39     * A non-standard extension that lets callers conveniently map back to the object
40     * their fd belongs to. This is used by Selector, for example, to associate each
41     * FileDescriptor with the corresponding SelectionKey.
42     */
43    public Object userData;
44
45    @Override public String toString() {
46        return "StructPollfd[fd=" + fd + ",events=" + events + ",revents=" + revents + "]";
47    }
48}
49