Using ANSI-C on Windows platform can I get time of system upto milliseconds accuracy?

Question

I need to get the millisecond accuracy. I take a look on this question but I am working on Windows: it gives linking errors for POSIX functions.

It will be very good if I can get UTC time since 1970 with milliseconds precision.

Answer 1

Sorry, but you can't do that using neither ANSI C nor the Windows API.

You can get the system time with a millisecond resolution using GetSystemTime or with a 100-nanosecond resolution using GetSystemTimeAsFileTime, but the accuracy will not be that good. The system time is only updated at each clock interval, which is somewhere around 10-15 milliseconds depending on the underlying architecture (SMP, Uniprocessor, ...).

There are ways to extrapolate the system time using different algorithms of varying complexity, but without the support of the operating system you'll never be guaranteed a correct high-resolution clock time.

Answer 2

In Windows API there is a SYSTEMTIME structure and some system calls to get system time and local time of your machine, you can implement it in this way:

SYSTEMTIME systime;
GetSystemTime(&systime);
unsigned int millisec = systime.wMilliseconds;