Author: Christophe Theron
Date: 10:02:38 10/09/99
Go up one level in this thread
On October 09, 1999 at 07:30:48, Vincent Lejeune wrote:
>On October 08, 1999 at 16:43:37, Christophe Theron wrote:
>
>>On October 08, 1999 at 06:14:23, Vincent Lejeune wrote:
>>
>>>On October 08, 1999 at 04:16:57, Christophe Theron wrote:
>>>
>>>>On October 08, 1999 at 03:42:54, Dave Gomboc wrote:
>>>>
>>>>>On October 07, 1999 at 23:29:05, Christophe Theron wrote:
>>>>>
>>>>>>That's a real problem on PC.
>>>>>>
>>>>>>The timer clicks 65536 times in 1 hour, which makes something close to 18.2
>>>>>>times per second, or a 0.05s timer resolution.
>>>>>>
>>>>>>This numbers come from the prehistoric IBM PC 4.77MHz and have never been
>>>>>>changed in 20 years, for compatibility reasons.
>>>>>>
>>>>>>Even Windows programmers did not dare to change this. You have time functions in
>>>>>>Windows, they returns values in milliseconds, but still the resolution is about
>>>>>>0.05s!!!
>>>>>
>>>>>Use performance tick counts if you develop for Win32. (Actually, I am not 100%
>>>>>sure that Win98 supports them. :-( WinNT does for sure.) Their resolution is
>>>>>very good.
>>>>>
>>>>>Dave
>>>>
>>>>Not sure this works. In the experiences I have done, the timer resolution was
>>>>always 0.05s. I'm pressimistic about getting something more accurate under
>>>>Windows 9x.
>>>>
>>>>This is not a big problem anyway...
>>>>
>>>>
>>>> Christophe
>>>
>>>I've tested the gettickcount() Win32 api, it's documented as have a 1
>>>millisecond time resolution and it have it effectivly.
>>>
>>>The win32 functions are usable in all Windows programming language (C++ (Borland
>>>and Microsoft), Delphi, ...)
>>
>>
>>Good to know. Thanks.
>>
>>
>> Christophe
>
>the gettickcount() function have one little drawback: it's a 32 bits variable.
>So every (about) 47 days, the counter going back to 0, you need to add simple
>test if the gettickcount()-starttime is < 0.
The (hand written) function I use currently has exactly the same problem, so it
is not a killer for me.
Christophe
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