text: 
  //          Copyright Oliver Kowalke 2017.
  // Distributed under the Boost Software License, Version 1.0.
  //    (See accompanying file LICENSE_1_0.txt or copy at
  //          http://www.boost.org/LICENSE_1_0.txt)
  
  #if defined(BOOST_USE_UCONTEXT)
  #include "boost/context/continuation_ucontext.hpp"
  #elif defined(BOOST_USE_WINFIB)
  #include "boost/context/continuation_winfib.hpp"
  #endif
  
  #include <boost/config.hpp>
  
  #ifdef BOOST_HAS_ABI_HEADERS
  # include BOOST_ABI_PREFIX
  #endif
  
  namespace boost {
  namespace context {
  namespace detail {
  
  // zero-initialization
  thread_local activation_record * current_rec;
  thread_local static std::size_t counter;
  
  // schwarz counter
  activation_record_initializer::activation_record_initializer() noexcept {
      if ( 0 == counter++) {
          current_rec = new activation_record();
      }
  }
  
  activation_record_initializer::~activation_record_initializer() {
      if ( 0 == --counter) {
          BOOST_ASSERT( current_rec->is_main_context() );
          delete current_rec;
      }
  }
  
  }
  
  namespace detail {
  
  activation_record *&
  activation_record::current() noexcept {
      // initialized the first time control passes; per thread
      thread_local static activation_record_initializer initializer;
      return current_rec;
  }
  
  }
  
  }}
  
  #ifdef BOOST_HAS_ABI_HEADERS
  # include BOOST_ABI_SUFFIX
  #endif
  