Question

I need to know how create a timer or measure out 500ms in C++ in a linux environment. I have tried using gettimeofday and using the time structure but cant get the correct precision for milliseconds. What I am trying to do is have an operation continue for a max of 500ms…after 500ms something else happens.

Answer 1

If you have access to C++11 then your best bet it to use std::chrono library

http://en.cppreference.com/w/cpp/chrono/duration

I aren’t entirely sure what you want to do with it do you want to wait for exactly 500ms?

you can so this for that

std::this_thread::sleep_for(std::chrono::milliseconds(500));

you can do an operation until 500 milliseconds has elapsed by getting a time pointer and check to see whether timepoint – system_time::now() is greater than 500ms

//if you compiler supports it you can use auto
std::chrono::system_clock::time_point start=std::chrono::system_clock::now();

while(start-std::chrono::system_clock::now() 
          < std::chrono::milliseconds(500))
{
    //do action
}

If you don’t have C++11 this will also work with boost chrono library. The advantage of this approach is that it is portable unlike using linux time functions.