Android Native代码中的status_t定义

定义在Android/system/core/include/utils/Errors.h中，小提示，Android代码中遇到的symbol，既不是Linux中提供的定义，使用source insight又找不到的情况下，可以去Android/system/core/include/目录找找，可能会有意想不到的收获哦。

定义如下：

1/*
2 * Copyright (C) 2007 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
17#ifndef ANDROID_ERRORS_H
18#define ANDROID_ERRORS_H
19
20#include 
21#include 
22
23namespace android {
24
25// use this type to return error codes
26#ifdef _WIN32
27typedef int         status_t;
28#else
29typedef int32_t     status_t;
30#endif
31
32/* the MS C runtime lacks a few error codes */
33
34/*
35 * Error codes.
36 * All error codes are negative values.
37 */
38
39// Win32 #defines NO_ERROR as well.  It has the same value, so there's no
40// real conflict, though it's a bit awkward.
41#ifdef _WIN32
42# undef NO_ERROR
43#endif
44
45enum {
46    OK                = 0,    // Everything's swell.
47    NO_ERROR          = 0,    // No errors.
48
49    UNKNOWN_ERROR       = (-2147483647-1), // INT32_MIN value
50
51    NO_MEMORY           = -ENOMEM,
52    INVALID_OPERATION   = -ENOSYS,
53    BAD_VALUE           = -EINVAL,
54    BAD_TYPE            = (UNKNOWN_ERROR + 1),
55    NAME_NOT_FOUND      = -ENOENT,
56    PERMISSION_DENIED   = -EPERM,
57    NO_INIT             = -ENODEV,
58    ALREADY_EXISTS      = -EEXIST,
59    DEAD_OBJECT         = -EPIPE,
60    FAILED_TRANSACTION  = (UNKNOWN_ERROR + 2),
61#if !defined(_WIN32)
62    BAD_INDEX           = -EOVERFLOW,
63    NOT_ENOUGH_DATA     = -ENODATA,
64    WOULD_BLOCK         = -EWOULDBLOCK,
65    TIMED_OUT           = -ETIMEDOUT,
66    UNKNOWN_TRANSACTION = -EBADMSG,
67#else
68    BAD_INDEX           = -E2BIG,
69    NOT_ENOUGH_DATA     = (UNKNOWN_ERROR + 3),
70    WOULD_BLOCK         = (UNKNOWN_ERROR + 4),
71    TIMED_OUT           = (UNKNOWN_ERROR + 5),
72    UNKNOWN_TRANSACTION = (UNKNOWN_ERROR + 6),
73#endif
74    FDS_NOT_ALLOWED     = (UNKNOWN_ERROR + 7),
75    UNEXPECTED_NULL     = (UNKNOWN_ERROR + 8),
76};
77
78// Restore define; enumeration is in "android" namespace, so the value defined
79// there won't work for Win32 code in a different namespace.
80#ifdef _WIN32
81# define NO_ERROR 0L
82#endif
83
84}; // namespace android
85
86// ---------------------------------------------------------------------------
87
88#endif // ANDROID_ERRORS_H
89

 所以，我们看到的status_t不过是int类型而已，只是取值有些枚举值已经定义好，当然也可以自己扩展。