clock

问题 BACKGROUND I'm creating an AJAX chat system. It looks something like this: Mike - hi Jane - 5 minutes ago Jane - hi Mike - 4 minutes ago Mike - how's it going - 3 seconds ago Jane - I'm doing good - 1 second ago Javascript polls the server every minute and the server responds with 10 of the newest messages. Attached to each message is a Unix timestamp (PHP time()). Javascript is responsible for merging the buffered messages the user currently has with this new server response. The

问题 I'm using the following short program to test std::clock() : #include <ctime> #include <iostream> int main() { std::clock_t Begin = std::clock(); int Dummy; std::cin >> Dummy; std::clock_t End = std::clock(); std::cout << "CLOCKS_PER_SEC: " << CLOCKS_PER_SEC << "\n"; std::cout << "Begin: " << Begin << "\n"; std::cout << "End: " << End << "\n"; std::cout << "Difference: " << (End - Begin) << std::endl; } However, after waiting several seconds to input the "dummy" value, I get the following

问题 I really don't think this question is a duplicate. Most answers to similar questions say to use System.currentTimeMillis() as the most accurate time, but I've noticed that two Android devices side-by-side may be off up to 5 seconds or more from each other or (more importantly) the real time, and I believe currentTimeMillis() will reflect that difference. So what I'm really looking for is a comprehensive solution to get the most accurate time possible in a given moment. For example, it would

问题 Are monotonic properties of std::chrono::steady_clock preserved across threads? For example, suppose I have the following program. #include <chrono> #include <mutex> #include <thread> using namespace std; using namespace chrono; mutex m; int i = 0; void do_something(int &x) { x += 1; } void f1() { unique_lock<mutex> lock(m); auto time = steady_clock::now(); do_something(i); } void f2() { unique_lock<mutex> lock(m); auto time = steady_clock::now(); do_something(i); } int main() { thread t1(f1)

问题 I am running a simulation that contains among other things a subsystem (or referenced model) that is a simulation by itself and that needs to be run fully at certain times before resuming the main simulation. Basically, at time t the main simulation needs the outputs of the subsystem. The subsystem is then triggered and runs a simulation for 6 seconds (the subsystem simulation is time dependent). Then the main simulation uses the outputs of the subsystem. The problem here is that when the

问题 I'm attempting to work with pixel data that is output to a DVI chip. A variety of clock frequencies are used because the DVI chip registers are programmed using I2C (therefore needs a clock < 500 KHz) - from a clock divider. The DVI chip needs a 40 MHz differential pixel clock, however, the DVI takes displays half a byte twice a cycle, so a further 80 MHz clock is needed to push each half of the pixel onto the data lines with each half cycle, these are from a DCM. This has led to a variety of

问题 This question already has an answer here : Is there any way to get the tamper-proof date and time on iPhone? (1 answer) Closed 5 years ago . So, I'm developing an app that is based on the time, but with NSDate an user can easily hack the application by changing system time of the device. So I might want to use a better method for retrieving time. How can I do this? Is there an easy way to retrieve time from internet? 回答1: Checkout this Google Library: https://github.com/jbenet/ios-ntp After

问题 We have a couple of ec2 instances on amazon, and we used amazon AIM Linux to set up. The instance type is m1.medium. Everything is going well until this week. We found from log file that there would be a huge clock drift happened suddenly, and sometimes there has a 5-minutes discrepancy。 I would like to ask if anyone else encounter this problem? How to deal with it? 回答1: Time drift can occur due to over utilization of your instances resources. I would encourage you to check you cloudwatch CPU

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 9 months ago . I wanted to make a simple program where the user has to enter a prompted number(1-4). Where the conditions of continuing is based on entering the number in the amount of time as defined by which level the user has selected and, of course, entering the correct number. The problem is that the program recognizes

问题 For solving metastability caused by different clock domains in Verilog, double-register method is used. But as far as I know, the final output of metastability is undetermined. Output is independent of input. So, my question is how to guarantee the correctness of output using double-register method? Thanks. 回答1: You cannot be completely sure that you avoided metastability. As you mentioned, the output of a metastable flip-flop is unpredictable so you can potentially propagate a wrong value