In my thread (using boost::thread) I need to retrieve the current time in ms or less and to convert into ms:
Actually, reading here I've found this:
tick = boost::posix_time::second_clock::local_time();
now = boost::posix_time::second_clock::local_time();
And seems to work, but after I need to have a long value of the milliseconds of the now...
How can I do it?
This question is related to
c++
boost
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timestamp
milliseconds
You can use boost::posix_time::time_duration to get the time range. E.g like this
boost::posix_time::time_duration diff = tick - now;
diff.total_milliseconds();
And to get a higher resolution you can change the clock you are using. For example to the boost::posix_time::microsec_clock, though this can be OS dependent. On Windows, for example, boost::posix_time::microsecond_clock has milisecond resolution, not microsecond.
An example which is a little dependent on the hardware.
int main(int argc, char* argv[])
{
boost::posix_time::ptime t1 = boost::posix_time::second_clock::local_time();
boost::this_thread::sleep(boost::posix_time::millisec(500));
boost::posix_time::ptime t2 = boost::posix_time::second_clock::local_time();
boost::posix_time::time_duration diff = t2 - t1;
std::cout << diff.total_milliseconds() << std::endl;
boost::posix_time::ptime mst1 = boost::posix_time::microsec_clock::local_time();
boost::this_thread::sleep(boost::posix_time::millisec(500));
boost::posix_time::ptime mst2 = boost::posix_time::microsec_clock::local_time();
boost::posix_time::time_duration msdiff = mst2 - mst1;
std::cout << msdiff.total_milliseconds() << std::endl;
return 0;
}
On my win7 machine. The first out is either 0 or 1000. Second resolution. The second one is nearly always 500, because of the higher resolution of the clock. I hope that help a little.
Try this: import headers as mentioned.. gives seconds and milliseconds only. If you need to explain the code read this link.
#include <windows.h>
#include <stdio.h>
void main()
{
SYSTEMTIME st;
SYSTEMTIME lt;
GetSystemTime(&st);
// GetLocalTime(<);
printf("The system time is: %02d:%03d\n", st.wSecond, st.wMilliseconds);
// printf("The local time is: %02d:%03d\n", lt.wSecond, lt.wMilliseconds);
}
If you mean milliseconds since epoch you could do
ptime time_t_epoch(date(1970,1,1));
ptime now = microsec_clock::local_time();
time_duration diff = now - time_t_epoch;
x = diff.total_milliseconds();
However, it's not particularly clear what you're after.
Have a look at the example in the documentation for DateTime at Boost Date Time
// Get current date/time in milliseconds.
#include "boost/date_time/posix_time/posix_time.hpp"
namespace pt = boost::posix_time;
int main()
{
pt::ptime current_date_microseconds = pt::microsec_clock::local_time();
long milliseconds = current_date_microseconds.time_of_day().total_milliseconds();
pt::time_duration current_time_milliseconds = pt::milliseconds(milliseconds);
pt::ptime current_date_milliseconds(current_date_microseconds.date(),
current_time_milliseconds);
std::cout << "Microseconds: " << current_date_microseconds
<< " Milliseconds: " << current_date_milliseconds << std::endl;
// Microseconds: 2013-Jul-12 13:37:51.699548 Milliseconds: 2013-Jul-12 13:37:51.699000
}
Source: Stackoverflow.com