C++ atomic::fetch_add方法代码示例

// run an inlet for some time (optionally with sporadic interruptions in between)
void run_inlet(const double duration_=0.0, const string name_=string(), const string type_=string(), const int in_chunks_=-1, const int request_info_=-1, const int request_time_=-1, const double seconds_between_failures_=0.0) {
	num_inlets.fetch_add(1);
	std::ostringstream s; s << boost::this_thread::get_id();
	srand((unsigned)boost::hash<string>()(s.str()));
	try {
		// choose random parameters if desired		
		double duration = (duration_ == 0.0) ? 1.0+rand()%(max_outlet_duration-1) : duration_;
		string name = name_.empty() ? names[rand()%(sizeof(names)/sizeof(names[0]))] : name_;
		string type = type_.empty() ? types[rand()%(sizeof(types)/sizeof(types[0]))] : type_;
		int request_info = (request_info_==-1) ? rand()%3 == 0 : request_info_;
		int request_time = (request_time_==-1) ? rand()%3 == 0 : request_time_;
		double seconds_between_failures = (seconds_between_failures_ == 0.0) ? (inlet_min_failure_interval_ms+rand()%outlet_max_failure_interval_ms)/1000.0 : seconds_between_failures_;

		// resolve by type...
		vector<lsl::stream_info> results = lsl::resolve_stream("type",type,1,5);
		if (results.empty())
			throw lsl::lost_error("No stream found.");
		lsl::stream_info result = results[rand()%results.size()];
		vector<float> chunk;		

		// and run...
		double t=0.0;
		for (double endtime = lsl::local_clock()+duration;lsl::local_clock()<endtime;) {
			// run a single execution of the inlet
			{
				cout << "new inlet(" << name << "," << type << ")...";
				lsl::stream_inlet inlet(result,max_buffered);
				cout << "done." << endl;
				int numchans = inlet.info().channel_count();
				init_sample(numchans*(int)ceil(max_chunk_len_ms*result.nominal_srate()/1000*max_chunk_oversize_factor),chunk);
				if (request_info) {
					cout << "  info = " << inlet.info(1.0).name() << endl;
				}
				for (double fail_at = lsl::local_clock()+seconds_between_failures;lsl::local_clock()<fail_at;) {
					boost::this_thread::sleep(boost::posix_time::milliseconds(1+rand()%max_inlet_poll_interval_ms));
					inlet.pull_chunk_multiplexed(&chunk[0],NULL,chunk.size(),0);
					if (request_time)
						t = inlet.time_correction(1.0);
				}
			}
			cout << "del inlet(" << name << "," << type << ")" << endl;
			if (request_time)
				cout << "  tcorr = " << t << endl;
			// downtime
			boost::this_thread::sleep(boost::posix_time::millisec(100*(rand()%50)));
		}
	} 
	catch(lsl::timeout_error &) { std::cerr << "Timeout exceeded; stopping inlet." << std::endl; }
	catch(lsl::lost_error &) { std::cerr << "Found no matching outlet; stopping inlet." << std::endl; }
	catch(std::exception &e) {
		std::cerr << "ERROR during run_inlet() Stress-test function: " <<	e.what() << std::endl;
	}
	num_inlets.fetch_sub(1);
}

    void call_void()
    {
        ++count_call_void;

        // make sure this function is not concurrently invoked
        HPX_TEST_EQ(count_active_call_void.fetch_add(1) + 1, 1);

        hpx::this_thread::suspend(boost::chrono::microseconds(100));

        --count_active_call_void;
        HPX_TEST_EQ(count_active_call_void.load(), 0);
    }

    explicit SessionMaintainerRequest(ApiFunctor * af) :
        af_(*af)
    {
#if ! defined(NDEBUG)
        const int object_count = session_maintainer_request_count.fetch_add(1,
            boost::memory_order_relaxed);
#       ifdef OUTPUT_DEBUG // Debug code
        std::cout << "++SessionMaintainerRequest: " << (object_count+1) << std::endl;
#       endif
        assert( object_count < 100000 );
#endif
    }

TORRENT_NO_RETURN TORRENT_EXPORT void assert_fail(char const* expr, int line
	, char const* file, char const* function, char const* value, int kind)
{
#ifdef TORRENT_PRODUCTION_ASSERTS
	// no need to flood the assert log with infinite number of asserts
	if (assert_counter.fetch_add(1) + 1 > 500) return;
#endif

	char stack[8192];
	stack[0] = '\0';
	print_backtrace(stack, sizeof(stack), 0);

	char const* message = "assertion failed. Please file a bugreport at "
		"http://code.google.com/p/libtorrent/issues\n"
		"Please include the following information:\n\n"
		"version: " LIBTORRENT_VERSION "\n"
		LIBTORRENT_REVISION "\n";

	switch (kind)
	{
		case 1:
			message = "A precondition of a libtorrent function has been violated.\n"
				"This indicates a bug in the client application using libtorrent\n";
	}
	  
	assert_print("%s\n"
#ifdef TORRENT_PRODUCTION_ASSERTS
		"#: %d\n"
#endif
		"file: '%s'\n"
		"line: %d\n"
		"function: %s\n"
		"expression: %s\n"
		"%s%s\n"
		"stack:\n"
		"%s\n"
		, message
#ifdef TORRENT_PRODUCTION_ASSERTS
		, assert_counter.load()
#endif
		, file, line, function, expr
		, value ? value : "", value ? "\n" : ""
		, stack);

	// if production asserts are defined, don't abort, just print the error
#ifndef TORRENT_PRODUCTION_ASSERTS
 	// send SIGINT to the current process
 	// to break into the debugger
 	raise(SIGINT);
 	abort();
#endif
}

// run an outlet for some time (optionally with sporadic interruptions in between)
void run_outlet(const double duration_=0.0, const string name_=string(), const string type_=string(), const int numchan_=0, const lsl::channel_format_t fmt_=lsl::cf_undefined, const double srate_=0.0, const double seconds_between_failures_=0.0, const int chunk_len_=0) {
	num_outlets.fetch_add(1);
	std::ostringstream s; s << boost::this_thread::get_id();
	srand((unsigned)boost::hash<string>()(s.str()));
	try {
		// choose random parameters if desired
		double duration = (duration_ == 0.0) ? 1.0+rand()%(max_outlet_duration-1) : duration_;
		string name = name_.empty() ? names[rand()%(sizeof(names)/sizeof(names[0]))] : name_;
		string type = type_.empty() ? types[rand()%(sizeof(types)/sizeof(types[0]))] : type_;
		int numchan = (numchan_ == 0) ? 1+(rand()%(max_channels-1)) : numchan_;
		double srate = (srate_ == 0.0) ? 1.0 + (rand()%(max_srate-1)) : srate_;
		lsl::channel_format_t fmt = (fmt_ == lsl::cf_undefined) ? fmts[rand()%6] : fmt_;
		double seconds_between_failures = (seconds_between_failures_ == 0.0) ? (inlet_min_failure_interval_ms+rand()%outlet_max_failure_interval_ms)/1000.0 : seconds_between_failures_;
		int chunk_len = (chunk_len_ == 0) ? std::max(min_chunk_len_ms,(rand()%max_chunk_len_ms)) : chunk_len_;

		// create a new streaminfo
		lsl::stream_info info(name,type,numchan,srate,fmt,boost::uuids::to_string(boost::uuids::random_generator()()));

		// initialize data to send
		vector<float> chunk;
		init_sample((int)(numchan*floor(chunk_len*srate/1000*max_chunk_oversize_factor)),chunk);

		// and run...
		for (double endtime = lsl::local_clock()+duration;lsl::local_clock()<endtime;) {
			// run a single execution of the outlet
			{
				cout << "new outlet(" << name << "," << type << "," << numchan << "," << fmt << "," << srate << ")...";
				lsl::stream_outlet outlet(info,0,max_buffered);
				cout << "done." << endl;
				// send in bursts
				double now, start_time = lsl::local_clock(), fail_at=start_time+seconds_between_failures;
				for (int target,diff,written=0;written<max_samples && !stop_outlet;written+=diff) {
					boost::this_thread::sleep(boost::posix_time::milliseconds(chunk_len));
					now = lsl::local_clock();
					if (now>fail_at)
						break;
					target = (int)floor((now-start_time)*srate);
					int num_elements = (int)std::min((std::size_t)((target-written)*numchan),chunk.size());
					if (num_elements)
						outlet.push_chunk_multiplexed(&chunk[0],num_elements);
					diff = num_elements/numchan;
				}
			}
			cout << "del outlet(" << name << "," << type << "," << numchan << "," << fmt << "," << srate << ")" << endl;
			// downtime
			boost::this_thread::sleep(boost::posix_time::millisec(100*(rand()%50)));
		}
	} catch(std::exception &e) {
		std::cerr << "ERROR during run_outlet() Stress-test function: " <<	e.what() << std::endl;
	}
	num_outlets.fetch_sub(1);
}

hpx::future<void> plain_future_void()
{
    ++count_plain_future_void;

    // make sure this function is not concurrently invoked
    HPX_TEST_EQ(count_active_plain_future_void.fetch_add(1) + 1, 1);

    hpx::this_thread::suspend(boost::chrono::microseconds(100));

    --count_active_plain_future_void;
    HPX_TEST_EQ(count_active_plain_future_void.load(), 0);

    return hpx::make_ready_future();
}

	void push_back(T elem) {
		// Construct an element to hold it
		synclist_item<T>* itm = new synclist_item<T>();
		itm->value = elem;
		itm->prev.store(m_last.load(boost::memory_order_release), boost::memory_order_acquire);
		itm->next.store(NULL, boost::memory_order_acquire);

		// Insert the element in the list
		synclist_item<T>* tmpItm = itm;
		synclist_item<T>* prevLast = m_last.exchange(tmpItm, boost::memory_order_consume);
		tmpItm = itm;
		synclist_item<T>* null = NULL;
		m_first.compare_exchange_strong(null, tmpItm, boost::memory_order_consume, boost::memory_order_acquire);
		if(prevLast != NULL) {
			prevLast->next.store(itm, boost::memory_order_consume);
		}
		m_length.fetch_add(1, boost::memory_order_consume);
	}

bool
test_arithmetic(boost::atomic<value_type> & shared_value, size_t instance)
{
    size_t shift = instance * 8;
    value_type mask = 0xff << shift;
    value_type increment = 1 << shift;

    value_type expected = 0;

    for (size_t n = 0; n < 255; n++) {
        value_type tmp = shared_value.fetch_add(increment, boost::memory_order_relaxed);
        if ( (tmp & mask) != (expected << shift) )
            return false;
        expected ++;
    }
    for (size_t n = 0; n < 255; n++) {
        value_type tmp = shared_value.fetch_sub(increment, boost::memory_order_relaxed);
        if ( (tmp & mask) != (expected << shift) )
            return false;
        expected --;
    }

    return true;
}

UString generateIDNumberString() {
	return uint64ToString(idNumberString.fetch_add(1));
}

uint32 generateIDNumber() {
	return idNumber.fetch_add(1);
}

void thread()
{
  a.fetch_add(1, boost::memory_order_relaxed);
}