libs/context/src/execution_context.cpp

   1
   2 //          Copyright Oliver Kowalke 2009.
   3 // Distributed under the Boost Software License, Version 1.0.
   4 //    (See accompanying file LICENSE_1_0.txt or copy at
   5 //          http://www.boost.org/LICENSE_1_0.txt)
   6
   7 #include "boost/context/detail/config.hpp"
   8
   9 #if ! defined(BOOST_CONTEXT_NO_CXX11)
  10
  11 #include "boost/context/execution_context.hpp"
  12 #include <boost/config.hpp>
  13
  14 #ifdef BOOST_HAS_ABI_HEADERS
  15 # include BOOST_ABI_PREFIX
  16 #endif
  17
  18 namespace boost {
  19 namespace context {
  20
  21 #if !defined(BOOST_NO_CXX11_THREAD_LOCAL)
  22
  23 namespace detail {
  24
  25 ecv1_activation_record::ptr_t &
  26 ecv1_activation_record::current() noexcept {
  27     thread_local static ptr_t current;
  28     return current;
  29 }
  30
  31 // zero-initialization
  32 thread_local static std::size_t counter;
  33
  34 // schwarz counter
  35 ecv1_activation_record_initializer::ecv1_activation_record_initializer() noexcept {
  36     if ( 0 == counter++) {
  37         ecv1_activation_record::current().reset( new ecv1_activation_record() );
  38     }
  39 }
  40
  41 ecv1_activation_record_initializer::~ecv1_activation_record_initializer() {
  42     if ( 0 == --counter) {
  43         BOOST_ASSERT( ecv1_activation_record::current()->is_main_context() );
  44         delete ecv1_activation_record::current().detach();
  45     }
  46 }
  47
  48 }
  49
  50 namespace v1 {
  51
  52 execution_context
  53 execution_context::current() noexcept {
  54     // initialized the first time control passes; per thread
  55     thread_local static detail::ecv1_activation_record_initializer initializer;
  56     return execution_context();
  57 }
  58
  59 }
  60
  61 #endif
  62
  63 }}
  64
  65 #ifdef BOOST_HAS_ABI_HEADERS
  66 # include BOOST_ABI_SUFFIX
  67 #endif
  68
  69 #endif