gecko-dev/mfbt/NullPtr.h

32 lines
916 B
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/. */
/* Implements a mozilla::IsNullPointer<T> type trait. */
#ifndef mozilla_NullPtr_h
#define mozilla_NullPtr_h
#include "mozilla/TypeTraits.h"
namespace mozilla {
/**
* IsNullPointer<T>::value is true iff T is decltype(nullptr).
*
* Ideally this would be in TypeTraits.h, but C++11 omitted std::is_null_pointer
* (fixed in C++14), so in the interests of easing a switch to <type_traits>,
* this trait lives elsewhere.
*/
template<typename T>
struct IsNullPointer : FalseType {};
template<>
struct IsNullPointer<decltype(nullptr)> : TrueType {};
}
#endif /* mozilla_NullPtr_h */