1*b0d29bc4SBrooks Davis // Copyright 2015 The Kyua Authors. 2*b0d29bc4SBrooks Davis // All rights reserved. 3*b0d29bc4SBrooks Davis // 4*b0d29bc4SBrooks Davis // Redistribution and use in source and binary forms, with or without 5*b0d29bc4SBrooks Davis // modification, are permitted provided that the following conditions are 6*b0d29bc4SBrooks Davis // met: 7*b0d29bc4SBrooks Davis // 8*b0d29bc4SBrooks Davis // * Redistributions of source code must retain the above copyright 9*b0d29bc4SBrooks Davis // notice, this list of conditions and the following disclaimer. 10*b0d29bc4SBrooks Davis // * Redistributions in binary form must reproduce the above copyright 11*b0d29bc4SBrooks Davis // notice, this list of conditions and the following disclaimer in the 12*b0d29bc4SBrooks Davis // documentation and/or other materials provided with the distribution. 13*b0d29bc4SBrooks Davis // * Neither the name of Google Inc. nor the names of its contributors 14*b0d29bc4SBrooks Davis // may be used to endorse or promote products derived from this software 15*b0d29bc4SBrooks Davis // without specific prior written permission. 16*b0d29bc4SBrooks Davis // 17*b0d29bc4SBrooks Davis // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 18*b0d29bc4SBrooks Davis // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 19*b0d29bc4SBrooks Davis // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 20*b0d29bc4SBrooks Davis // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 21*b0d29bc4SBrooks Davis // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 22*b0d29bc4SBrooks Davis // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 23*b0d29bc4SBrooks Davis // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24*b0d29bc4SBrooks Davis // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25*b0d29bc4SBrooks Davis // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26*b0d29bc4SBrooks Davis // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 27*b0d29bc4SBrooks Davis // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28*b0d29bc4SBrooks Davis 29*b0d29bc4SBrooks Davis /// \file utils/optional_fwd.hpp 30*b0d29bc4SBrooks Davis /// Forward declarations for utils/optional.hpp 31*b0d29bc4SBrooks Davis 32*b0d29bc4SBrooks Davis #if !defined(UTILS_OPTIONAL_FWD_HPP) 33*b0d29bc4SBrooks Davis #define UTILS_OPTIONAL_FWD_HPP 34*b0d29bc4SBrooks Davis 35*b0d29bc4SBrooks Davis namespace utils { 36*b0d29bc4SBrooks Davis 37*b0d29bc4SBrooks Davis 38*b0d29bc4SBrooks Davis namespace detail { 39*b0d29bc4SBrooks Davis 40*b0d29bc4SBrooks Davis 41*b0d29bc4SBrooks Davis /// Internal type-safe representation for the none type. 42*b0d29bc4SBrooks Davis struct none_t {}; 43*b0d29bc4SBrooks Davis 44*b0d29bc4SBrooks Davis 45*b0d29bc4SBrooks Davis } // namespace detail 46*b0d29bc4SBrooks Davis 47*b0d29bc4SBrooks Davis 48*b0d29bc4SBrooks Davis /// The none value. 49*b0d29bc4SBrooks Davis /// 50*b0d29bc4SBrooks Davis /// This has internal linkage so it is OK to define it in the header file. 51*b0d29bc4SBrooks Davis /// However, pointers to none from different translation units will be 52*b0d29bc4SBrooks Davis /// different. Just don't do that. 53*b0d29bc4SBrooks Davis const detail::none_t none = {}; 54*b0d29bc4SBrooks Davis 55*b0d29bc4SBrooks Davis 56*b0d29bc4SBrooks Davis template< class > class optional; 57*b0d29bc4SBrooks Davis 58*b0d29bc4SBrooks Davis 59*b0d29bc4SBrooks Davis } // namespace utils 60*b0d29bc4SBrooks Davis 61*b0d29bc4SBrooks Davis #endif // !defined(UTILS_OPTIONAL_FWD_HPP) 62