chanmo
asked on
SYSTEMTIME arithmetic
I want to obtain the time difference between 2 SYSTEMTIME variables. I'm recommended to convert them to ULARGE_INTEGER before doing subtraction. But I don't know how to do ULARGE_INTEGER arithmetics. Please suggest some ways to get the SYSTEMTIME difference. I would also like to know how can I add 5 minutes to a SYSTEMTIME variable containing the current time. Thank you.
chanmo,
a easier structure for your purpose is FILETIME.
You can convert a SYSTEMTIME-object into FILETIME with
SystemTimeToFileTime()
then cast it to LARGE_INTEGER and do your operations.
See SDK doc of FILETIME for further information
a easier structure for your purpose is FILETIME.
You can convert a SYSTEMTIME-object into FILETIME with
SystemTimeToFileTime()
then cast it to LARGE_INTEGER and do your operations.
See SDK doc of FILETIME for further information
ASKER
I know I can convert SYSTEMTIME to FILETIME. My problem is I don't know how to do ULARGE_INTEGER (or LARGE_INTEGER) arithmetic operations. Is it that I should cast the member of LARGE_INTEGER to __int64 and then use the operators? When I did this to calculate the difference between 2 SYSTEMTIME differed by 5 seconds, the result was 1601/1/1 00:00:05. So I want to know whether there is a better way to obtain "5 seconds" as result. I also want to know what I should do if I want to add 5 minutes to a SYSTEMTIME returned by GetLocalTime().
If you are using MFC, try to use CTime class, it's quite convenient.
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ASKER
Thank you very much for your help!
ASKER