Android Native代码中的status_t定义

谁践踏了优雅 2022-05-17 10:43 157阅读 0赞

## 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 <sys/types.h>
    21#include <errno.h>
    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。 ##