webrtc/rtc_base/system/unused.h
Fredrik Solenberg 500e75b467 Remove typedefs.h from webrtc/ root (part 1)
Bug: webrtc:6854
Change-Id: Iadbc73d1913a507c0097ade82b6e406cbfa30a64
Reviewed-on: https://webrtc-review.googlesource.com/78062
Reviewed-by: Niels Moller <nisse@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Fredrik Solenberg <solenberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#23362}
2018-05-23 12:07:10 +00:00

39 lines
1.4 KiB
C

/*
* Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef RTC_BASE_SYSTEM_UNUSED_H_
#define RTC_BASE_SYSTEM_UNUSED_H_
// Annotate a function indicating the caller must examine the return value.
// Use like:
// int foo() RTC_WARN_UNUSED_RESULT;
// To explicitly ignore a result, cast to void.
// TODO(kwiberg): Remove when we can use [[nodiscard]] from C++17.
#if defined(__clang__)
#define RTC_WARN_UNUSED_RESULT __attribute__((__warn_unused_result__))
#elif defined(__GNUC__)
// gcc has a __warn_unused_result__ attribute, but you can't quiet it by
// casting to void, so we don't use it.
#define RTC_WARN_UNUSED_RESULT
#else
#define RTC_WARN_UNUSED_RESULT
#endif
// Prevent the compiler from warning about an unused variable. For example:
// int result = DoSomething();
// assert(result == 17);
// RTC_UNUSED(result);
// Note: In most cases it is better to remove the unused variable rather than
// suppressing the compiler warning.
#ifndef RTC_UNUSED
#define RTC_UNUSED(x) static_cast<void>(x)
#endif // RTC_UNUSED
#endif // RTC_BASE_SYSTEM_UNUSED_H_