StructPollfd.java revision fe77f817b540f2a66c17486a618bb9083a22070e 
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 android.system;
18
19import java.io.FileDescriptor;
20import libcore.util.Objects;
21
22/**
23 * Corresponds to C's {@code struct pollfd} from
24 * <a href="http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/poll.h.html">&lt;poll.h&gt;</a>
25 *
26 * @hide
27 */
28public final class StructPollfd {
29  /** The file descriptor to poll. */
30  public FileDescriptor fd;
31
32  /**
33   * The events we're interested in. POLLIN corresponds to being in select(2)'s read fd set,
34   * POLLOUT to the write fd set.
35   */
36  public short events;
37
38  /** The events that actually happened. */
39  public short revents;
40
41  /**
42   * A non-standard extension that lets callers conveniently map back to the object
43   * their fd belongs to. This is used by Selector, for example, to associate each
44   * FileDescriptor with the corresponding SelectionKey.
45   */
46  public Object userData;
47
48  @Override public String toString() {
49    return Objects.toString(this);
50  }
51}
52