ceph/src/boost/libs/coroutine/example/symmetric/segmented_stack.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/coroutine/all.hpp>
   8
   9 #include <iostream>
  10
  11 #include <boost/assert.hpp>
  12 #include <boost/config.hpp>
  13 #include <boost/thread.hpp>
  14
  15 int count = 384;
  16
  17 #ifdef BOOST_MSVC //MS VisualStudio
  18 __declspec(noinline) void access( char *buf);
  19 #else // GCC
  20 void access( char *buf) __attribute__ ((noinline));
  21 #endif
  22 void access( char *buf)
  23 {
  24   buf[0] = '\0';
  25 }
  26
  27 void bar( int i)
  28 {
  29     char buf[4 * 1024];
  30
  31     if ( i > 0)
  32     {
  33         access( buf);
  34         std::cout << i << ". iteration" << std::endl;
  35         bar( i - 1);
  36     }
  37 }
  38
  39 void foo( boost::coroutines::symmetric_coroutine< void >::yield_type &)
  40 {
  41     bar( count);
  42 }
  43
  44 void thread_fn()
  45 {
  46     {
  47         boost::coroutines::symmetric_coroutine< void >::call_type coro( foo);
  48         coro();
  49     }
  50 }
  51
  52 int main( int argc, char * argv[])
  53 {
  54 #if defined(BOOST_USE_SEGMENTED_STACKS)
  55     std::cout << "using segmented stacks: allocates " << count << " * 4kB == " << 4 * count << "kB on stack, ";
  56     std::cout << "initial stack size = " << boost::coroutines::stack_allocator::traits_type::default_size() / 1024 << "kB" << std::endl;
  57     std::cout << "application should not fail" << std::endl;
  58 #else
  59     std::cout << "using standard stacks: allocates " << count << " * 4kB == " << 4 * count << "kB on stack, ";
  60     std::cout << "initial stack size = " << boost::coroutines::stack_allocator::traits_type::default_size() / 1024 << "kB" << std::endl;
  61     std::cout << "application might fail" << std::endl;
  62 #endif
  63
  64     boost::thread( thread_fn).join();
  65
  66     return 0;
  67 }