ceph/src/boost/boost/contract/detail/static_local_var.hpp

   1
   2 #ifndef BOOST_CONTRACT_DETAIL_STATIC_LOCAL_VAR_HPP_
   3 #define BOOST_CONTRACT_DETAIL_STATIC_LOCAL_VAR_HPP_
   4
   5 // Copyright (C) 2008-2018 Lorenzo Caminiti
   6 // Distributed under the Boost Software License, Version 1.0 (see accompanying
   7 // file LICENSE_1_0.txt or a copy at http://www.boost.org/LICENSE_1_0.txt).
   8 // See: http://www.boost.org/doc/libs/release/libs/contract/doc/html/index.html
   9
  10 namespace boost { namespace contract { namespace detail {
  11
  12 // This is used to hold the state of this library (already checking assertions,
  13 // failure handers, mutexes, etc.). Local static variables are used instead of
  14 // global or class-level static variables to avoid ODR errors when this library
  15 // is used as header-only.
  16
  17 // Use T's default constructor to init the local var.
  18 template<typename Tag, typename T>
  19 struct static_local_var {
  20     static T& ref() {
  21         static T data;
  22         return data;
  23     }
  24 };
  25
  26 // Use `init` param to init local var (Init same as or convertible to T).
  27 // NOTE: Template specializations could be used to program both this and the
  28 // template above together but some pre-C++11 compilers give errors (e.g., Clang
  29 // without -std=c++11), plus the `_init` postfix is more readable at call site.
  30 template<typename Tag, typename T, typename Init, Init init>
  31 struct static_local_var_init {
  32     static T& ref() {
  33         static T data = init;
  34         return data;
  35     }
  36 };
  37
  38 } } } // namespace
  39
  40 #endif // #include guard
  41