| Fredrik Solenberg | 500e75b | 2018-05-23 11:49:01 +0200 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2018 The WebRTC project authors. All Rights Reserved. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license |
| 5 | * that can be found in the LICENSE file in the root of the source |
| 6 | * tree. An additional intellectual property rights grant can be found |
| 7 | * in the file PATENTS. All contributing project authors may |
| 8 | * be found in the AUTHORS file in the root of the source tree. |
| 9 | */ |
| 10 | |
| 11 | #ifndef RTC_BASE_SYSTEM_UNUSED_H_ |
| 12 | #define RTC_BASE_SYSTEM_UNUSED_H_ |
| 13 | |
| 14 | // Annotate a function indicating the caller must examine the return value. |
| 15 | // Use like: |
| 16 | // int foo() RTC_WARN_UNUSED_RESULT; |
| 17 | // To explicitly ignore a result, cast to void. |
| 18 | // TODO(kwiberg): Remove when we can use [[nodiscard]] from C++17. |
| 19 | #if defined(__clang__) |
| 20 | #define RTC_WARN_UNUSED_RESULT __attribute__((__warn_unused_result__)) |
| 21 | #elif defined(__GNUC__) |
| 22 | // gcc has a __warn_unused_result__ attribute, but you can't quiet it by |
| 23 | // casting to void, so we don't use it. |
| 24 | #define RTC_WARN_UNUSED_RESULT |
| 25 | #else |
| 26 | #define RTC_WARN_UNUSED_RESULT |
| 27 | #endif |
| 28 | |
| 29 | // Prevent the compiler from warning about an unused variable. For example: |
| 30 | // int result = DoSomething(); |
| 31 | // assert(result == 17); |
| 32 | // RTC_UNUSED(result); |
| 33 | // Note: In most cases it is better to remove the unused variable rather than |
| 34 | // suppressing the compiler warning. |
| 35 | #ifndef RTC_UNUSED |
| 36 | #define RTC_UNUSED(x) static_cast<void>(x) |
| 37 | #endif // RTC_UNUSED |
| 38 | |
| 39 | #endif // RTC_BASE_SYSTEM_UNUSED_H_ |