gecko-dev/mfbt/Unused.h

40 lines
1.0 KiB
C++

/* -*- 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/Attributes.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>
MOZ_ALWAYS_INLINE_EVEN_DEBUG 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