在Windows平台上使用ansi-c我可以获得系统时间精确​​到毫秒级吗？

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

不是在ANSI C中，但Windows API提供了GetSystemTime函数，如下所示： http ： //msdn.microsoft.com/en-us/library/ms724950（ GetSystemTime .aspx

Answer 2

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 3

In windows api there is a SYSTEMTIME structure and some sys calls to get systemtime and localtime of your machine, you can implement it in this way:

SYSTEMTIME systime;

GetSystemTime(&systime);

unsigned int millisec = systime.wMilliseconds;