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Message |
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Chuck Benso
#1 / 9
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 Timer Function Accuracy Hello,
I am trying to use the Timer function to measure the interval between 2
events in a single process app. Is there a way to reliably determine the
accuracy of this interval? Ie can I count on 3 decimal places? 2 ? 1?
Thanks,
Chuck
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| Sun, 23 Mar 2003 09:58:01 GMT |
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Jason
#2 / 9
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Timer Function Accuracy In my experience I have found the Timer object that VB provides to give accuracy to around 0ms to +50ms.
That is
if you set the timer to 200ms it could trigger anywhere between 200ms and 250ms although most of the time
unless the timer is set to below 50ms it is usually accurate within a few ms except under heavy system
load when you could even miss events.
Jason
Quote:
> Hello, > I am trying to use the Timer function to measure the interval between 2 > events in a single process app. Is there a way to reliably determine the > accuracy of this interval? Ie can I count on 3 decimal places? 2 ? 1? > Thanks,
> Chuck
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| Sun, 23 Mar 2003 10:59:51 GMT |
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Chuck Benso
#3 / 9
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Timer Function Accuracy Jason,
Thanks. You were referring to the Timer Control (and not the Timer
function), right? Do you think the same holds true for the Timer function?
Thanks,
Chuck
Quote: > In my experience I have found the Timer object that VB provides to give
accuracy to around 0ms to +50ms.
Quote: > That is
> if you set the timer to 200ms it could trigger anywhere between 200ms and
250ms although most of the time
Quote: > unless the timer is set to below 50ms it is usually accurate within a few
ms except under heavy system
Quote: > load when you could even miss events. > Jason
> > Hello,
> > I am trying to use the Timer function to measure the interval between 2
> > events in a single process app. Is there a way to reliably determine
the
> > accuracy of this interval? Ie can I count on 3 decimal places? 2 ? 1?
> > Thanks,
> > Chuck
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| Sun, 23 Mar 2003 11:41:02 GMT |
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Ian
#4 / 9
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Timer Function Accuracy Hi Chuck
Use this to time your event
Declare Function timeGetTime Lib "winmm" () As Long
This returns a Long which which represents the number of milli-seconds
Windows has been running.
regards
Ian
** invalid email address, change dk to denmark
homepage http://www.kingsoft-denmark.com/
Tips & Tricks page http://tips.kingsoft-denmark.com/
Quote: > Hello, > I am trying to use the Timer function to measure the interval between 2 > events in a single process app. Is there a way to reliably determine the > accuracy of this interval? Ie can I count on 3 decimal places? 2 ? 1? > Thanks,
> Chuck
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| Sun, 23 Mar 2003 14:47:31 GMT |
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Fedor Solodovni
#5 / 9
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Timer Function Accuracy Hi!
Use of QueryPerformanceFrequency and QueryPerformanceCounter gives the
best results for Your task
Good luck
Quote:
> Hello,
> I am trying to use the Timer function to measure the interval between 2
> events in a single process app. Is there a way to reliably determine the
> accuracy of this interval? Ie can I count on 3 decimal places? 2 ? 1?
> Thanks,
> Chuck
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| Wed, 18 Jun 1902 08:00:00 GMT |
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Johan Bechthu
#6 / 9
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Timer Function Accuracy Chuck,
in a new project, use the following code:
===================================
Option Explicit
Dim mStartTime As Single
Private Sub Form_MouseDown(Button As Integer, Shift As Integer, X As Single,
Y As Single)
Caption = "Mouse-button is down"
mStartTime = Timer
End Sub
Private Sub Form_MouseUp(Button As Integer, Shift As Integer, X As Single, Y
As Single)
Dim StopTime As Single
StopTime = Timer
Caption = "Mouse-button was down for " & StopTime - mStartTime & "
seconds"
End Sub
===================================
It gives me an elapsed time with the accuracy if a single (7 positions).
Johan.
| Hello,
| I am trying to use the Timer function to measure the interval between 2
| events in a single process app. Is there a way to reliably determine the
| accuracy of this interval? Ie can I count on 3 decimal places? 2 ? 1?
|
| Thanks,
| Chuck
|
|
|
| Wed, 18 Jun 1902 08:00:00 GMT |
|
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|
#7 / 9
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Timer Function Accuracy
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| Wed, 18 Jun 1902 08:00:00 GMT |
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Chuck Benso
#8 / 9
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Timer Function Accuracy Thanks again.
I am trying to implement QueryPerformanceFrequency and
QueryPerformanceCounter as function, but am having a few problems.
1) When I try to paste in the declaration (from API Viewer in VB6), my VB
environment wants to drop some of the code. For example, the original is --
Private Declare Function QueryPerformanceFrequency Lib "kernel32" Alias
"QueryPerformanceFrequency" (lpFrequency As LARGE_INTEGER) As Long
But it gets truncated to --
Private Declare Function QueryPerformanceFrequency Lib "kernel32"
(lpFrequency As LARGE_INTEGER) As Long
Is there a way to avoid this?
I keep getting User-Defined Type not Defined
2) Do I need to make a copy of the kernel32 file to somewhere in the VB
environment?
Thanks,
Chuck
Quote: > Hi! > Use of QueryPerformanceFrequency and QueryPerformanceCounter gives the > best results for Your task > Good luck
> > Hello,
> > I am trying to use the Timer function to measure the interval between 2
> > events in a single process app. Is there a way to reliably determine
the
> > accuracy of this interval? Ie can I count on 3 decimal places? 2 ? 1?
> > Thanks,
> > Chuck
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| Wed, 18 Jun 1902 08:00:00 GMT |
|
|
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Chuck Benso
#9 / 9
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Timer Function Accuracy Answer to my own question --
Change LARGE_INTEGER to Long and it worked. Didn't need the 'Alias' part
either.
Chuck
Quote: > Thanks again. > I am trying to implement QueryPerformanceFrequency and
> QueryPerformanceCounter as function, but am having a few problems.
> 1) When I try to paste in the declaration (from API Viewer in VB6), my VB
> environment wants to drop some of the code. For example, the original
is --
> Private Declare Function QueryPerformanceFrequency Lib "kernel32" Alias
> "QueryPerformanceFrequency" (lpFrequency As LARGE_INTEGER) As Long
> But it gets truncated to --
> Private Declare Function QueryPerformanceFrequency Lib "kernel32"
> (lpFrequency As LARGE_INTEGER) As Long
> Is there a way to avoid this?
> I keep getting User-Defined Type not Defined
> 2) Do I need to make a copy of the kernel32 file to somewhere in the VB
> environment?
> Thanks,
> Chuck
> > Hi!
> > Use of QueryPerformanceFrequency and QueryPerformanceCounter gives the
> > best results for Your task
> > Good luck
> > > Hello,
> > > I am trying to use the Timer function to measure the interval between
2
> > > events in a single process app. Is there a way to reliably determine
> the
> > > accuracy of this interval? Ie can I count on 3 decimal places? 2 ? 1?
> > > Thanks,
> > > Chuck
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| Wed, 18 Jun 1902 08:00:00 GMT |
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| |
