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May 28th, 2024, 11:03 PM
#31
Re: VB6 - A very precise timer using Multithreading
Code:
Will produce a timer error accumulation, 10 times delay of 1 second, the final error reached about 6 milliseconds
Cumulative time: 10005.4726 ms
1, time: 999.5706 milliseconds
2, time: 1001.004 milliseconds
3, time: 999.9972 milliseconds
4, time: 1000.9968 milliseconds
5, time: 1001.0024 milliseconds
6, time: 1000.0044 milliseconds
7, time: 1000.0083 milliseconds
8, time: 1000.9891 milliseconds
9, time: 1000.9963 milliseconds
10, time: 1000.9035 milliseconds
Code:
Private Type FILETIME
dwLowDateTime As Long
dwHighDateTime As Long
End Type
Private Const WAIT_ABANDONED& = &H80&
Private Const WAIT_ABANDONED_0& = &H80&
Private Const WAIT_FAILED& = -1&
Private Const WAIT_IO_COMPLETION& = &HC0&
Private Const WAIT_OBJECT_0& = 0
Private Const WAIT_OBJECT_1& = 1
Private Const WAIT_TIMEOUT& = &H102&
Private Const INFINITE = &HFFFF
Private Const QS_HOTKEY& = &H80
Private Const QS_KEY& = &H1
Private Const QS_MOUSEBUTTON& = &H4
Private Const QS_MOUSEMOVE& = &H2
Private Const QS_PAINT& = &H20
Private Const QS_POSTMESSAGE& = &H8
Private Const QS_SENDMESSAGE& = &H40
Private Const QS_TIMER& = &H10
Private Const ERROR_ALREADY_EXISTS = 183&
Private Const QS_MOUSE& = (QS_MOUSEMOVE Or QS_MOUSEBUTTON)
Private Const QS_INPUT& = (QS_MOUSE Or QS_KEY)
Private Const QS_ALLEVENTS& = (QS_INPUT Or QS_POSTMESSAGE Or QS_TIMER Or QS_PAINT Or QS_HOTKEY)
Private Const QS_ALLINPUT& = (QS_SENDMESSAGE Or QS_PAINT Or QS_TIMER Or QS_POSTMESSAGE Or QS_MOUSEBUTTON Or QS_MOUSEMOVE Or QS_HOTKEY Or QS_KEY)
Private Const UNITS = 4294967296#
Private Const MAX_LONG = -2147483648#
Private Declare Function CreateWaitableTimer _
Lib "kernel32" _
Alias "CreateWaitableTimerA" (ByVal lpSemaphoreAttributes As Long, _
ByVal bManualReset As Long, _
ByVal lpName As String) As Long
Private Declare Function OpenWaitableTimer _
Lib "kernel32" _
Alias "OpenWaitableTimerA" (ByVal dwDesiredAccess As Long, _
ByVal bInheritHandle As Long, _
ByVal lpName As String) As Long
Private Declare Function SetWaitableTimer _
Lib "kernel32" (ByVal hTimer As Long, _
lpDueTime As FILETIME, _
ByVal lPeriod As Long, _
ByVal pfnCompletionRoutine As Long, _
ByVal lpArgToCompletionRoutine As Long, _
ByVal fResume As Long) As Long
Private Declare Function CancelWaitableTimer Lib "kernel32" (ByVal hTimer As Long)
Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long
Private Declare Function WaitForSingleObject _
Lib "kernel32" (ByVal hHandle As Long, _
ByVal dwMilliseconds As Long) As Long
Private Declare Function MsgWaitForMultipleObjects _
Lib "user32" (ByVal nCount As Long, _
pHandles As Long, _
ByVal fWaitAll As Long, _
ByVal dwMilliseconds As Long, _
ByVal dwWakeMask As Long) As Long
Private mlTimer As Long
Sub StartTimer4()
Randomize
mlTimer = CreateWaitableTimer(0, True, App.EXEName & "Timer" & Format$(Now(), "NNSS") & Int(Rnd * 10000))
If Err.LastDllError = ERROR_ALREADY_EXISTS Then
MsgBox "TIMER ERR"
End If
End Sub
Sub CloseTimer4()
On Error Resume Next
If mlTimer <> 0 Then CloseHandle mlTimer
End Sub
Public Sub WaitCounts(MilliSeconds As Currency, Counts As Long)
On Error GoTo ErrHandler
Dim ft As FILETIME
Dim lBusy As Long
Dim lRet As Long
Dim dblDelay As Double
Dim dblDelayLow As Double
ft.dwLowDateTime = -1
ft.dwHighDateTime = -1
lRet = SetWaitableTimer(mlTimer, ft, 0, 0, 0, 0)
'CDbl
dblDelay = CCur(MilliSeconds) * 10000#
ft.dwHighDateTime = -CLng(dblDelay / UNITS) - 1
dblDelayLow = -UNITS * (dblDelay / UNITS - Fix(CStr(dblDelay / UNITS)))
If dblDelayLow < MAX_LONG Then dblDelayLow = UNITS + dblDelayLow
ft.dwLowDateTime = CLng(dblDelayLow)
Dim ID As Long
Dim UsedC() As Currency, StartC As Currency
ReDim UsedC(0 To Counts)
QueryPerformanceCounter CPUv1
StartC = CPUv1
lRet = SetWaitableTimer(mlTimer, ft, 0, 0, 0, False)
Do While True
lBusy = MsgWaitForMultipleObjects(1, mlTimer, False, INFINITE, QS_ALLINPUT&)
If lBusy = WAIT_OBJECT_0 Then
ID = ID + 1
QueryPerformanceCounter CPUv2
UsedC(ID) = CPUv2
If ID = Counts Then Exit Do
'QueryPerformanceCounter CPUv1
CPUv1 = CPUv2
SetWaitableTimer mlTimer, ft, 0, 0, 0, False
Else
DoEvents
End If
Loop
' CloseHandle mlTimer
' mlTimer = 0
Dim i As Long
UsedC(0) = StartC
Debug.Print "All UsedTime?" & (CPUv2 - StartC) / MsCount & "ms"
For i = 1 To 10
Debug.Print i & ",Used?" & (UsedC(i) - UsedC(i - 1)) / MsCount & "ms"
Next
Exit Sub
ErrHandler:
Err.Raise Err.Number, Err.Source, "[clsWaitableTimer.Wait]" & Err.Description
End Sub
Code:
Private Sub Form_Load()
timeBeginPeriod 1
StartTimer4
End Sub
Private Sub Form_QueryUnload(Cancel As Integer, UnloadMode As Integer)
CloseTimer4
End Sub
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