mfbt/Unused.h
author Gijs Kruitbosch <gijskruitbosch@gmail.com>
Wed, 31 May 2017 14:15:18 +0100
changeset 410456 4f3980aa447fda41b2b082195b5addd1417733cf
parent 352423 54c1dcc180bf043c881ee3ca92b34d016ad917af
child 413998 57b1aa6bfa2e43322cc2318916352a3fea19d19d
permissions -rw-r--r--
Bug 1359137 - fix BrowserUITelemetry's reliance on the default state of things in CustomizableUI, r=mikedeboer MozReview-Commit-ID: I4mpVR6G8pi

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_unused_h
#define mozilla_unused_h

#include "mozilla/Types.h"

#ifdef __cplusplus

namespace mozilla {

//
// Suppress GCC warnings about unused return values with
//   Unused << SomeFuncDeclaredWarnUnusedReturnValue();
//
struct unused_t
{
  template<typename T>
  inline void
  operator<<(const T& /*unused*/) const {}
};

extern MFBT_DATA const unused_t Unused;

} // namespace mozilla

#endif // __cplusplus

// An alternative to mozilla::Unused for use in (a) C code and (b) code where
// linking with unused.o is difficult.
#define MOZ_UNUSED(expr) \
  do { if (expr) { (void)0; } } while (0)

#endif // mozilla_unused_h