doc/html/boost_asio/example/timers/tick_count_timer.cpp
//
// tick_count_timer.cpp
// ~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2008 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// 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/asio.hpp>
#include <ctime>
#include <iostream>
#if defined(WIN32)
# include <windows.h>
#else
# error This example is for Windows only!
#endif
struct tick_count_traits
{
// The time type. This type has no constructor that takes a DWORD to ensure
// that the timer can only be used with relative times.
class time_type
{
public:
time_type() : ticks_(0) {}
private:
friend struct tick_count_traits;
DWORD ticks_;
};
// The duration type.
class duration_type
{
public:
duration_type() : ticks_(0) {}
duration_type(DWORD ticks) : ticks_(ticks) {}
private:
friend struct tick_count_traits;
DWORD ticks_;
};
// Get the current time.
static time_type now()
{
time_type result;
result.ticks_ = ::GetTickCount();
return result;
}
// Add a duration to a time.
static time_type add(const time_type& t, const duration_type& d)
{
time_type result;
result.ticks_ = t.ticks_ + d.ticks_;
return result;
}
// Subtract one time from another.
static duration_type subtract(const time_type& t1, const time_type& t2)
{
return duration_type(t1.ticks_ - t2.ticks_);
}
// Test whether one time is less than another.
static bool less_than(const time_type& t1, const time_type& t2)
{
// DWORD tick count values wrap periodically, so we'll use a heuristic that
// says that if subtracting t1 from t2 yields a value smaller than 2^31,
// then t1 is probably less than t2. This means that we can't handle
// durations larger than 2^31, which shouldn't be a problem in practice.
return (t2.ticks_ - t1.ticks_) < static_cast<DWORD>(1 << 31);
}
// Convert to POSIX duration type.
static boost::posix_time::time_duration to_posix_duration(
const duration_type& d)
{
return boost::posix_time::milliseconds(d.ticks_);
}
};
typedef boost::asio::basic_deadline_timer<
DWORD, tick_count_traits> tick_count_timer;
void handle_timeout(const boost::system::error_code&)
{
std::cout << "handle_timeout\n";
}
int main()
{
try
{
boost::asio::io_service io_service;
tick_count_timer timer(io_service, 5000);
std::cout << "Starting synchronous wait\n";
timer.wait();
std::cout << "Finished synchronous wait\n";
timer.expires_from_now(5000);
std::cout << "Starting asynchronous wait\n";
timer.async_wait(handle_timeout);
io_service.run();
std::cout << "Finished asynchronous wait\n";
}
catch (std::exception& e)
{
std::cout << "Exception: " << e.what() << "\n";
}
return 0;
}