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