src/gromacs/utility/nodelete.h

   1 /*
   2  * This file is part of the GROMACS molecular simulation package.
   3  *
   4  * Copyright (c) 2015,2018, by the GROMACS development team, led by
   5  * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
   6  * and including many others, as listed in the AUTHORS file in the
   7  * top-level source directory and at http://www.gromacs.org.
   8  *
   9  * GROMACS is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public License
  11  * as published by the Free Software Foundation; either version 2.1
  12  * of the License, or (at your option) any later version.
  13  *
  14  * GROMACS is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with GROMACS; if not, see
  21  * http://www.gnu.org/licenses, or write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA.
  23  *
  24  * If you want to redistribute modifications to GROMACS, please
  25  * consider that scientific software is very special. Version
  26  * control is crucial - bugs must be traceable. We will be happy to
  27  * consider code for inclusion in the official distribution, but
  28  * derived work must not be called official GROMACS. Details are found
  29  * in the README & COPYING files - if they are missing, get the
  30  * official version at http://www.gromacs.org.
  31  *
  32  * To help us fund GROMACS development, we humbly ask that you cite
  33  * the research papers on the package. Check out http://www.gromacs.org.
  34  */
  35 /*! \libinternal \file
  36  * \brief
  37  * Declares no_delete deleter for std::shared_ptr.
  38  *
  39  * \author Teemu Murtola <teemu.murtola@gmail.com>
  40  * \inlibraryapi
  41  * \ingroup module_utility
  42  */
  43 #ifndef GMX_UTILITY_NODELETE_H
  44 #define GMX_UTILITY_NODELETE_H
  45
  46 namespace gmx
  47 {
  48
  49 /*! \libinternal \brief
  50  * Deleter for std::shared_ptr that does nothing.
  51  *
  52  * This is useful for cases where a class needs to keep a reference to another
  53  * class, and optionally also manage the lifetime of that other class.
  54  * The simplest construct (that does not force all callers to use heap
  55  * allocation and std::shared_ptr for the referenced class) is to use a
  56  * single std::shared_ptr to hold that reference, and use no_delete as the
  57  * deleter if the lifetime is managed externally.
  58  *
  59  * \inlibraryapi
  60  * \ingroup module_utility
  61  */
  62 template <class T>
  63 struct no_delete
  64 {
  65     //! Deleter that does nothing.
  66     void operator()(T * /*unused*/) {}
  67 };
  68
  69 } // namespace gmx
  70
  71 #endif