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// (C) Copyright 2006-7 Anthony Williams
// 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)
#include <boost/test/unit_test.hpp>
#include <boost/thread/thread.hpp>
#include <boost/thread/mutex.hpp>
#include <boost/thread/once.hpp>
boost::once_flag flag=BOOST_ONCE_INIT;
int var_to_init=0;
boost::mutex m;
void initialize_variable()
{
// ensure that if multiple threads get in here, they are serialized, so we can see the effect
boost::mutex::scoped_lock lock(m);
++var_to_init;
}
void call_once_thread()
{
unsigned const loop_count=100;
int my_once_value=0;
for(unsigned i=0;i<loop_count;++i)
{
boost::call_once(flag, initialize_variable);
my_once_value=var_to_init;
if(my_once_value!=1)
{
break;
}
}
boost::mutex::scoped_lock lock(m);
BOOST_CHECK_EQUAL(my_once_value, 1);
}
void test_call_once()
{
unsigned const num_threads=20;
boost::thread_group group;
try
{
for(unsigned i=0;i<num_threads;++i)
{
group.create_thread(&call_once_thread);
}
group.join_all();
}
catch(...)
{
group.interrupt_all();
group.join_all();
throw;
}
BOOST_CHECK_EQUAL(var_to_init,1);
}
int var_to_init_with_functor=0;
struct increment_value
{
int* value;
explicit increment_value(int* value_):
value(value_)
{}
void operator()() const
{
boost::mutex::scoped_lock lock(m);
++(*value);
}
};
void call_once_with_functor()
{
unsigned const loop_count=100;
int my_once_value=0;
static boost::once_flag functor_flag=BOOST_ONCE_INIT;
for(unsigned i=0;i<loop_count;++i)
{
boost::call_once(functor_flag, increment_value(&var_to_init_with_functor));
my_once_value=var_to_init_with_functor;
if(my_once_value!=1)
{
break;
}
}
boost::mutex::scoped_lock lock(m);
BOOST_CHECK_EQUAL(my_once_value, 1);
}
void test_call_once_arbitrary_functor()
{
unsigned const num_threads=20;
boost::thread_group group;
try
{
for(unsigned i=0;i<num_threads;++i)
{
group.create_thread(&call_once_with_functor);
}
group.join_all();
}
catch(...)
{
group.interrupt_all();
group.join_all();
throw;
}
BOOST_CHECK_EQUAL(var_to_init_with_functor,1);
}
struct throw_before_third_pass
{
struct my_exception
{};
static unsigned pass_counter;
void operator()() const
{
boost::mutex::scoped_lock lock(m);
++pass_counter;
if(pass_counter<3)
{
throw my_exception();
}
}
};
unsigned throw_before_third_pass::pass_counter=0;
unsigned exception_counter=0;
void call_once_with_exception()
{
static boost::once_flag functor_flag=BOOST_ONCE_INIT;
try
{
boost::call_once(functor_flag, throw_before_third_pass());
}
catch(throw_before_third_pass::my_exception)
{
boost::mutex::scoped_lock lock(m);
++exception_counter;
}
}
void test_call_once_retried_on_exception()
{
unsigned const num_threads=20;
boost::thread_group group;
try
{
for(unsigned i=0;i<num_threads;++i)
{
group.create_thread(&call_once_with_exception);
}
group.join_all();
}
catch(...)
{
group.interrupt_all();
group.join_all();
throw;
}
BOOST_CHECK_EQUAL(throw_before_third_pass::pass_counter,3u);
BOOST_CHECK_EQUAL(exception_counter,2u);
}
boost::unit_test_framework::test_suite* init_unit_test_suite(int, char*[])
{
boost::unit_test_framework::test_suite* test =
BOOST_TEST_SUITE("Boost.Threads: call_once test suite");
test->add(BOOST_TEST_CASE(test_call_once));
test->add(BOOST_TEST_CASE(test_call_once_arbitrary_functor));
test->add(BOOST_TEST_CASE(test_call_once_retried_on_exception));
return test;
}
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