GetTickCount has been deprecated in favor of GetTickCount64, which gives
a qword result and so it "solves" the wrap-arount to 0 of the tick after
49.7 days, so one doesn't have to worry that the expression
GetTickCount64-PreviousTick
will ever give a negative result, and
if GetTickCount64-PreviousTick>WaitTime then
is guaranteed to work for the next ~500 millions years.
However GetTickCount64 isn't available in windows XP, so the rtl
simulates it by using.....GetTickCount, with the result that the above
"if" condition could fail after 49.7 days.
For that I still have to use DWORDs instead of qwords and cast the
subtraction to DWORD (so that the rollback doesn't matter as long as the
WaitTime above is less than $ffffffff)
BEFORE (with gettickcount):
----------------------------------------------------------------------
var PreviousTick:DWORD;
...
PreviousTick:=GetTickCount;
...
... if DWORD(GetTickCount-PreviousTick)>WaitTime then....
----------------------------------------------------------------------
NOW (with gettickcount64)
----------------------------------------------------------------------
var PreviousTick:QWORD;
...
PreviousTick:=GetTickCount64;
...
... if GetTickCount64-PreviousTick>WaitTime then....
----------------------------------------------------------------------
Which seems cleaner but isn't really guaranteed to work, so I have to:
----------------------------------------------------------------------
var PreviousTick:DWORD;
...
PreviousTick:=DWORD(GetTickCount64);
...
... if DWORD(DWORD(GetTickCount64)-PreviousTick)>WaitTime then....
----------------------------------------------------------------------
wouldn't have been better to just leave GetTickCount alone, without
deprecation (and maybe give a warning that GetTickCount64 doesn't give a
usable result on all platforms)?
Bye
--
Luca
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