ceph/src/boost/libs/type_index/examples/registry.cpp

   1 // Copyright 2013-2022 Antony Polukhin
   2
   3 // Distributed under the Boost Software License, Version 1.0.
   4 // (See the accompanying file LICENSE_1_0.txt
   5 // or a copy at <http://www.boost.org/LICENSE_1_0.txt>.)
   6
   7 //[type_index_registry_example
   8 /*`
   9     The following example shows how an information about a type could be stored.
  10     Example works with and without RTTI.
  11 */
  12
  13 #include <boost/type_index.hpp>
  14 #include <boost/unordered/unordered_set.hpp>
  15 //<-
  16 // Making `#include <cassert>` visible in docs, while actually using `BOOST_TEST`
  17 // instead of `assert`. This is required to verify correct behavior even if NDEBUG
  18 // is defined and to avoid `unused local variable` warnings with defined NDEBUG.
  19 //
  20 // boost-no-inspect
  21 #include <boost/core/lightweight_test.hpp>
  22 #ifdef assert
  23 #   undef assert
  24 #endif
  25 #define assert(X) BOOST_TEST(X)
  26     /* !Comment block is not closed intentionaly!
  27 //->
  28 #include <cassert>
  29 //<-
  30     !Closing comment block! */
  31 //->
  32
  33 int main() {
  34     boost::unordered_set<boost::typeindex::type_index> types;
  35
  36     // Storing some `boost::type_info`s
  37     types.insert(boost::typeindex::type_id<int>());
  38     types.insert(boost::typeindex::type_id<float>());
  39
  40     // `types` variable contains two `boost::type_index`es:
  41     assert(types.size() == 2);
  42
  43     // Const, volatile and reference will be striped from the type:
  44     bool is_inserted = types.insert(boost::typeindex::type_id<const int>()).second;
  45     assert(!is_inserted);
  46     assert(types.erase(boost::typeindex::type_id<float&>()) == 1);
  47
  48     // We have erased the `float` type, only `int` remains
  49     assert(*types.begin() == boost::typeindex::type_id<int>());
  50 //<-
  51     return boost::report_errors();
  52 //->
  53 }
  54
  55 //] [/type_index_registry_example]