1 // Copyright (C) 2001-2003 2 // William E. Kempf 3 // 4 // Distributed under the Boost Software License, Version 1.0. (See accompanying 5 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 6 7 #include <boost/thread/thread.hpp> 8 #include <boost/thread/once.hpp> 9 #include <cassert> 10 11 int value=0; 12 boost::once_flag once = BOOST_ONCE_INIT; 13 init()14void init() 15 { 16 ++value; 17 } 18 thread_proc()19void thread_proc() 20 { 21 boost::call_once(&init, once); 22 } 23 main(int argc,char * argv[])24int main(int argc, char* argv[]) 25 { 26 boost::thread_group threads; 27 for (int i=0; i<5; ++i) 28 threads.create_thread(&thread_proc); 29 threads.join_all(); 30 assert(value == 1); 31 } 32