00001 /*---------------------------------------------------------------------------*\ 00002 ========= | 00003 \\ / F ield | OpenFOAM: The Open Source CFD Toolbox 00004 \\ / O peration | 00005 \\ / A nd | Copyright (C) 1991-2010 OpenCFD Ltd. 00006 \\/ M anipulation | 00007 ------------------------------------------------------------------------------- 00008 License 00009 This file is part of OpenFOAM. 00010 00011 OpenFOAM is free software: you can redistribute it and/or modify it 00012 under the terms of the GNU General Public License as published by 00013 the Free Software Foundation, either version 3 of the License, or 00014 (at your option) any later version. 00015 00016 OpenFOAM is distributed in the hope that it will be useful, but WITHOUT 00017 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 00018 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 00019 for more details. 00020 00021 You should have received a copy of the GNU General Public License 00022 along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>. 00023 00024 Class 00025 Foam::nil 00026 00027 Description 00028 A zero-sized class without any storage. Used, for example, in HashSet. 00029 00030 Note 00031 A zero-sized class actually does still require at least 1 byte storage. 00032 00033 \*---------------------------------------------------------------------------*/ 00034 00035 #ifndef nil_H 00036 #define nil_H 00037 00038 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // 00039 00040 namespace Foam 00041 { 00042 00043 // Forward declaration of classes 00044 class Istream; 00045 class Ostream; 00046 00047 // Forward declaration of friend functions and operators 00048 00049 class nil; 00050 00051 Istream& operator>>(Istream&, nil&); 00052 Ostream& operator<<(Ostream&, const nil&); 00053 00054 00055 /*---------------------------------------------------------------------------*\ 00056 Class nil Declaration 00057 \*---------------------------------------------------------------------------*/ 00058 00059 class nil 00060 { 00061 00062 public: 00063 00064 // Constructors 00065 00066 //- Construct null 00067 nil() 00068 {} 00069 00070 //- Construct from Istream 00071 nil(Istream&) 00072 {} 00073 00074 00075 // IOstream Operators 00076 00077 friend Istream& operator>>(Istream& is, nil&) 00078 { 00079 return is; 00080 } 00081 00082 friend Ostream& operator<<(Ostream& os, const nil&) 00083 { 00084 return os; 00085 } 00086 }; 00087 00088 00089 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // 00090 00091 } // End namespace Foam 00092 00093 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * // 00094 00095 #endif 00096 00097 // ************************ vim: set sw=4 sts=4 et: ************************ //
