getUTCtime() increases irregularly

[david]

Frits van Bommel schrieb:
> david wrote:
>> I was just playing with a slow down class, when I noticed
>> getUTCtime() from std.date works a bit unexpected:
>>
>> import std.stdio;
>> import std.date : getUTCtime;
>>
>> int main(char[][] args)
>> {
>>     for (int i=0;i<500;i++)
>>         writefln(getUTCtime());
>>     return 0;
>> }
>>
>> results in (shortened version, for obvious reasons):
>>
> [snip]
>>
>> So, it increases as well in large increments
>> and also in irregular ones, namely
>> 15 and 16 milliseconds.
>>
>> Since I found nothing in the phobos docs,
>> how can I access the current time at a more
>> precise level?
> 
> The precision of the clock is operating-system dependent AFAIK. 
> (including the version of the OS and obviously the type of machine it's 
> running on)
> D can't make it more accurate than the OS is willing to provide :(.
> 
> (Your post header indicates you're running Windows)
> On Windows, there are (at least) two functions to get the current time: 
> one returns it as a SYSTEMTIME structure, one as a FILETIME structure. 
> It looks like std.date uses GetSystemTime; you could try to see if 
> GetFileTime is more accurate. (no idea why it would be, but you could 
> try...)
> Try this:
> ---
> import std.c.windows.windows : GetSystemTimeAsFileTime, FILETIME;
> import std.date;
> 
> d_time currentFileTime() {
>     FILETIME ft;
>     GetSystemTimeAsFileTime(&ft);
>     return std.date.FILETIME2D_time(ft);
> }
> ---
> (Coded with no access to a Windows computer, so completely untested. I 
> just had the std.date source and pages referenced from 
> http://msdn2.microsoft.com/en-us/library/ms725479.aspx to work with)

Thanks for the idea,
but as you thought the precision is the same,
d_time currentFileTime()
{
     FILETIME ft;
     GetSystemTimeAsFileTime(&ft);
     return std.date.FILETIME2d_time(&ft);
}
yields the same result as getUTCtime().
(And for that matter, as a direct GetSystemTime().)