TimerEx, hi precision timer using QueryPerformanceCounter

[Elroy]

You are (obviously) welcome to read all the posts in this thread. But I've made additional comments in post #26 that may be of interest to you.

I've posted this class many times in specific question threads, and I'm often referring to it, so I thought I'd post it here. It's just a high precision timer using the QueryPerformanceCounter API call.

I'm posting the entire CLS code (including the header stuff). So, to use it, open Notepad (or any ASCII editor), past it in, and save as TimerEx.cls. I've also attached in in the attached ZIP.

As a note, it's got the VB_PredeclaredId flag set to True. That can only be done to a CLS module with Notepad, and can't be done from the VB6 IDE. But, once done, it works perfectly. This flag auto instantiates the CLS module, using the CLS module's name as the object variable name. (Forms have this VB_PredeclaredId flag set to True by default. That's why you can use their names as an object variable that auto instantiates.)

With this VB_PredeclaredId = True, there's no need to declare any variable. Just start using the TimerEx, and it'll just work. It basically just becomes another keyword in the VB6 language.

There is only one read-only property (actually a function) named Value. However, it has it's Value.VB_UserMemId set to 0. This means it's the default. So you don't even have to say TimerEx.Value. You can just say TimerEx to get the value.

As a final note, if you use this for timing tests (which it's very good at), be sure to just get a value from TimerEx before you start your timings. Any CLS declared with New or with its VB_PredeclaredId flag set to True will be instantiated the first time you touch it, and not before. Therefore, you don't want your instantiation time interfering with anything, so "touch" it before using it in a critical way, and then it'll stay instantiated (unless you explicitly set it to Nothing).

Here's the code (with header info):

VERSION 1.0 CLASS
BEGIN
  MultiUse = -1  'True
  Persistable = 0  'NotPersistable
  DataBindingBehavior = 0  'vbNone
  DataSourceBehavior  = 0  'vbNone
  MTSTransactionMode  = 0  'NotAnMTSObject
END
Attribute VB_Name = "TimerEx"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
'
' This class has VB_PredeclaredId = True.
' Also, the Value is set to the default property.
' Therefore, TimerEx will just act like a new built-in function.
' No need to declare an object variable or explicitly instantiate.
'
Option Explicit
'
Private Declare Function QueryPerformanceCounter Lib "kernel32" (lpPerformanceCount As Currency) As Long
Private Declare Function QueryPerformanceFrequency Lib "kernel32" (lpFrequency As Currency) As Long
'
Private cFreq As Currency
'

Private Sub Class_Initialize()
    QueryPerformanceFrequency cFreq
End Sub

Public Function Value() As Double
Attribute Value.VB_UserMemId = 0
    ' Must be Public (not Friend) so we can set default property.
    ' Returns seconds, a double, with high-precision.
    ' Caller is responsible for keeping track of start/stop times.
    ' Basically, it works exactly like the built-in Timer function, but with much more precision.
    Dim cValue As Currency
    QueryPerformanceCounter cValue
    Value = cValue / cFreq  ' The division will return a double, and it also cancels out the Currency decimal points.
End Function

And, the attachment is below.

Enjoy,
Elroy

EDIT1: Just as a notice, this TimerEx returns the number of seconds elapsed since the system on which it's running was last booted. And, AFAIK, it never rolls over. A Double can easily hold enough seconds that your computer would crumble to dust before it would need to roll over. This is in contrast to the built-in Timer function, which is pegged at midnight, and rolls over each day. Typically, I only use these things for Deltas (differences) so I don't care about their zero basis.