VBA High-Res Stopwatch Code

2023-11-23 14:53 UTC gpt-4 Open in ChatGPT ↗

Explain in great detail and professional verbosity what this Stopwatch code does, and why VERSION 1.0 CLASS BEGIN MultiUse = -1 ‘True END Attribute VB_Name = “Stopwatch” Attribute VB_GlobalNameSpace = False Attribute VB_Creatable = False Attribute VB_PredeclaredId = False Attribute VB_Exposed = False ‘Dylan: This is not my code, all I did was turn the seconds elapsed into ms elapsed ‘Code from here https://bytecomb.com/accurate-performance-timers-in-vba/

Option Explicit

#If Win64 Then Private Declare PtrSafe Function QueryPerformanceCounter Lib “kernel32” (lpPerformanceCount As UINT64) As Long Private Declare PtrSafe Function QueryPerformanceFrequency Lib “kernel32” (lpFrequency As UINT64) As Long #Else Private Declare Function QueryPerformanceCounter Lib “kernel32” (lpPerformanceCount As UINT64) As Long Private Declare Function QueryPerformanceFrequency Lib “kernel32” (lpFrequency As UINT64) As Long #End If

Private pFrequency As Double Private pStartTS As UINT64 Private pEndTS As UINT64 Private pElapsed As Double Public msElapsed As Double Private pRunning As Boolean

Private Type UINT64 LowPart As Long HighPart As Long End Type

Private Const BSHIFT_32 = 4294967296# ’ 2 ^ 32

Private Function U64Dbl(U64 As UINT64) As Double Dim lDbl As Double, hDbl As Double lDbl = U64.LowPart hDbl = U64.HighPart If lDbl < 0 Then lDbl = lDbl + BSHIFT_32 If hDbl < 0 Then hDbl = hDbl + BSHIFT_32 U64Dbl = lDbl + BSHIFT_32 * hDbl End Function

Private Sub Class_Initialize() Dim PerfFrequency As UINT64 QueryPerformanceFrequency PerfFrequency pFrequency = U64Dbl(PerfFrequency) End Sub

Public Property Get Elapsed() As Double If pRunning Then Dim pNow As UINT64 QueryPerformanceCounter pNow Elapsed = pElapsed + (U64Dbl(pNow) - U64Dbl(pStartTS)) / pFrequency Elapsed = Elapsed * 1000 Else Elapsed = pElapsed Elapsed = Elapsed * 1000 End If End Property

Public Sub start() If Not pRunning Then QueryPerformanceCounter pStartTS pRunning = True End If End Sub

Public Sub Pause() If pRunning Then QueryPerformanceCounter pEndTS pRunning = False pElapsed = pElapsed + (U64Dbl(pEndTS) - U64Dbl(pStartTS)) / pFrequency End If End Sub

Public Sub Reset() pElapsed = 0 pRunning = False End Sub

Public Sub Restart() pElapsed = 0 QueryPerformanceCounter pStartTS pRunning = True End Sub

Public Property Get Running() As Boolean Running = pRunning End Property

This code is a VBA (Visual Basic for Applications) class module for a high-resolution stopwatch. It’s designed to measure time intervals with a high degree of accuracy. Let’s dissect its components and functionalities:

Module and Class Attributes:
- MultiUse, VB_Name, VB_GlobalNameSpace, VB_Creatable, VB_PredeclaredId, VB_Exposed are attributes defining how the class behaves within the VBA environment. For example, VB_Creatable = False prevents the creation of an instance of this class using a New keyword in VBA.
- A comment indicates that this is not the original author’s code and refers to a source for the original code.
Conditional Compilation:
- The code uses #If Win64 Then directive to declare functions differently based on whether it is running on a 64-bit system (PtrSafe keyword for compatibility).
API Declarations:
- QueryPerformanceCounter and QueryPerformanceFrequency are Windows API functions imported from kernel32.dll. They are used to get high-resolution time stamps and the frequency of the high-resolution performance counter, crucial for calculating elapsed time.
Private Variables:
- Variables like pFrequency, pStartTS, pEndTS, pElapsed, msElapsed, and pRunning are used to store the frequency of the performance counter, start and end timestamps, elapsed time, elapsed time in milliseconds, and the running state of the stopwatch, respectively.
Custom Data Type and Constants:
- UINT64 is a custom data type representing a 64-bit unsigned integer, which is crucial for high-resolution timing.
- BSHIFT_32 is a constant representing 2^32, used in converting 64-bit integers to doubles.
Utility Function:
- U64Dbl converts UINT64 to a Double. It’s essential for accurate time calculation.
Class Initialization:
- In the Class_Initialize subroutine, the frequency of the high-resolution performance counter is retrieved and converted to a double for later calculations.
Elapsed Time Calculation:
- The Elapsed property calculates the elapsed time in milliseconds. It accounts for whether the stopwatch is currently running or not.
Control Methods:
- Start, Pause, Reset, and Restart methods control the stopwatch’s state. Start initiates timing, Pause stops it temporarily, Reset clears the elapsed time, and Restart resets and starts the stopwatch anew.
Running State Property:
- The Running property is a read-only property that returns the current state of the stopwatch (running or not).

In essence, this code provides a precise and versatile stopwatch functionality in VBA, suitable for performance measurement or timing operations where standard timing functions are not accurate enough. The integration with Windows API functions allows it to achieve higher precision than the native VBA timing functions.

Sure, let’s go through the code step-by-step and explain the operations in detail:

Module and Class Attributes:
- MultiUse = -1: This indicates that the class can be instantiated multiple times.
- Attribute VB_*: These attributes define the behavior and properties of the class within the VBA environment.
Conditional Compilation:
- #If Win64 Then...#Else...#End If: This part checks if the VBA is running on a 64-bit system. If true, it uses the PtrSafe keyword for API declarations to ensure compatibility with 64-bit systems.
API Declarations:
- QueryPerformanceCounter: This function retrieves the current value of the high-resolution performance counter, which counts the number of ticks (or units of time) since the system was started.
- QueryPerformanceFrequency: This function retrieves the frequency of the high-resolution performance counter. This frequency value is used to convert the counter value into a time unit.
Private Variables:
- pFrequency: Stores the frequency of the high-resolution counter in ticks per second.
- pStartTS, pEndTS: Variables to store the start and end timestamps (in ticks) of the timer.
- pElapsed: Stores the elapsed time in seconds.
- msElapsed: Public variable to store the elapsed time in milliseconds.
- pRunning: Boolean to track whether the stopwatch is running.
Custom Data Type and Constants:
- Private Type UINT64: A custom data type to handle 64-bit numbers (since VBA doesn’t natively support 64-bit integers).
- BSHIFT_32: A constant equal to 2^32, used for arithmetic operations on 64-bit numbers.
U64Dbl Function:
- U64Dbl: This function converts a 64-bit number (UINT64) into a double-precision floating-point number. It’s crucial because VBA does not natively handle 64-bit integers, and this conversion allows for precise time calculations.
Class Initialization (Class_Initialize):
- Retrieves and stores the frequency of the high-resolution performance counter in pFrequency when an instance of the class is created.
Elapsed Time Calculation (Elapsed Property):
- If the stopwatch is running, it calculates the elapsed time by getting the current performance counter value, subtracting the start timestamp, dividing by the frequency (to convert to seconds), and then multiplying by 1000 to convert to milliseconds.
- If the stopwatch is not running, it simply returns the already calculated elapsed time.
Control Methods (Start, Pause, Reset, Restart):
- Start: Sets the start timestamp and marks the stopwatch as running.
- Pause: Calculates the elapsed time until the pause, updates pElapsed, and marks the stopwatch as not running.
- Reset: Resets the elapsed time to zero and marks the stopwatch as not running.
- Restart: Resets the elapsed time and starts the stopwatch anew.
Running State Property (Running):
- A read-only property that returns whether the stopwatch is currently running.

In summary, this code is a sophisticated VBA implementation of a stopwatch using high-resolution performance counters provided by the Windows API. It’s designed for scenarios where precision timing is crucial, such as in performance testing or benchmarking tasks. The use of 64-bit integers and conversion to double precision ensures accuracy in timing calculations.

Certainly! Below is a version of the stopwatch code with detailed comments for each section and operation:

VERSION 1.0 CLASS
BEGIN
  MultiUse = -1  'True - Allows multiple instances of this class
END
Attribute VB_Name = "Stopwatch"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False   ' Prevents creating an instance using the New keyword
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
'Dylan: Modified code for ms elapsed. Original from https://bytecomb.com/accurate-performance-timers-in-vba/

Option Explicit

' Conditional compilation for 64-bit or 32-bit system
#If Win64 Then
    ' Declare API functions with PtrSafe for 64-bit compatibility
    Private Declare PtrSafe Function QueryPerformanceCounter Lib "kernel32" (lpPerformanceCount As UINT64) As Long
    Private Declare PtrSafe Function QueryPerformanceFrequency Lib "kernel32" (lpFrequency As UINT64) As Long
#Else
    ' Declare API functions for 32-bit system
    Private Declare Function QueryPerformanceCounter Lib "kernel32" (lpPerformanceCount As UINT64) As Long
    Private Declare Function QueryPerformanceFrequency Lib "kernel32" (lpFrequency As UINT64) As Long
#End If

' Private variables for internal workings of the stopwatch
Private pFrequency As Double  ' Frequency of the high-resolution performance counter
Private pStartTS As UINT64    ' Start timestamp
Private pEndTS As UINT64      ' End timestamp
Private pElapsed As Double    ' Elapsed time in seconds
Public msElapsed As Double    ' Elapsed time in milliseconds
Private pRunning As Boolean   ' Flag indicating if the stopwatch is running

' Custom data type for handling 64-bit numbers
Private Type UINT64
    LowPart As Long
    HighPart As Long
End Type

' Constant for bitwise shift operations (2^32)
Private Const BSHIFT_32 = 4294967296#

' Function to convert a 64-bit number to Double
Private Function U64Dbl(U64 As UINT64) As Double
    Dim lDbl As Double, hDbl As Double
    lDbl = U64.LowPart
    hDbl = U64.HighPart
    If lDbl < 0 Then lDbl = lDbl + BSHIFT_32 ' Adjust for negative values
    If hDbl < 0 Then hDbl = hDbl + BSHIFT_32 ' Adjust for negative values
    U64Dbl = lDbl + BSHIFT_32 * hDbl         ' Convert to Double
End Function

' Initialize the stopwatch class
Private Sub Class_Initialize()
    Dim PerfFrequency As UINT64
    QueryPerformanceFrequency PerfFrequency
    pFrequency = U64Dbl(PerfFrequency) ' Store the frequency for timing calculations
End Sub

' Property to get the elapsed time in milliseconds
Public Property Get Elapsed() As Double
    If pRunning Then
        Dim pNow As UINT64
        QueryPerformanceCounter pNow
        Elapsed = pElapsed + (U64Dbl(pNow) - U64Dbl(pStartTS)) / pFrequency
    Else
        Elapsed = pElapsed
    End If
    Elapsed = Elapsed * 1000 ' Convert seconds to milliseconds
End Property

' Start or resume the stopwatch
Public Sub start()
    If Not pRunning Then
        QueryPerformanceCounter pStartTS ' Set the start timestamp
        pRunning = True                 ' Mark as running
    End If
End Sub

' Pause the stopwatch
Public Sub Pause()
    If pRunning Then
        QueryPerformanceCounter pEndTS   ' Get the end timestamp
        pRunning = False                ' Mark as not running
        pElapsed = pElapsed + (U64Dbl(pEndTS) - U64Dbl(pStartTS)) / pFrequency ' Update elapsed time
    End If
End Sub

' Reset the stopwatch
Public Sub Reset()
    pElapsed = 0   ' Reset elapsed time
    pRunning = False ' Mark as not running
End Sub

' Restart the stopwatch
Public Sub Restart()
    pElapsed = 0                   ' Reset elapsed time
    QueryPerformanceCounter pStartTS ' Set the start timestamp
    pRunning = True                 ' Mark as running
End Sub

' Property to check if the stopwatch is running
Public Property Get Running() As Boolean
   Running = pRunning
End Property

This code provides a detailed and commented version of the stopwatch implementation in VBA, making it easier to understand and maintain. Each section and function is annotated to explain its purpose and how it contributes to the overall functionality of the stopwatch.

Creating a test function in Excel to automatically test the precision of the stopwatch class involves a few steps. We need to write a VBA function that will use the stopwatch to measure the time taken by a known and consistent process, and then compare this measured time against the expected time. This will give us an idea of the precision of the stopwatch. Here’s an example of how you can do it:

Create a Dummy Task Function: First, we need a task with a predictable duration. This could be a simple loop that runs for a specific number of iterations.
Test Function: This function will use the Stopwatch class to time how long the dummy task takes to complete. It will then compare this duration to the expected duration.
Output: The test function can output the measured time, the expected time, and the difference between the two, giving an indication of the precision of the stopwatch.

Here’s an example implementation in VBA:

' Dummy task function that takes a predictable amount of time
Function DummyTask(iterations As Long)
    Dim i As Long
    For i = 1 To iterations
        ' Simple operation that takes a measurable amount of time
        DoEvents
    Next i
End Function

' Test function for the stopwatch
Function TestStopwatchPrecision()
    Dim sw As New Stopwatch
    Dim measuredTime As Double
    Dim expectedTime As Double
    Dim iterations As Long
    Dim precision As Double

    iterations = 100000 ' Number of iterations for the dummy task
    expectedTime = 2    ' Expected time in milliseconds (adjust based on your system)

    ' Start the stopwatch, perform the task, then stop the stopwatch
    sw.Start
    DummyTask iterations
    sw.Pause
    measuredTime = sw.Elapsed ' Time measured by the stopwatch

    ' Calculate the precision
    precision = Abs((measuredTime - expectedTime) / expectedTime) * 100

    ' Output the results
    Debug.Print "Measured Time: " & measuredTime & " ms"
    Debug.Print "Expected Time: " & expectedTime & " ms"
    Debug.Print "Precision: " & precision & "% difference"

End Function

To run this test, you would place both the DummyTask function and the TestStopwatchPrecision function in a VBA module within Excel. You would then call TestStopwatchPrecision from the Immediate Window in the VBA editor or from another subroutine or function.

Please adjust the expectedTime and iterations values based on your system’s performance and the precision you are expecting. The DoEvents function in DummyTask is used to ensure that the task takes a measurable amount of time, but it’s a simplistic approach and may need adjustment for more accurate testing.

You’re correct in noting that creating a function with a truly predictable duration is challenging, especially in an environment like Excel VBA, where many factors can influence execution time. However, for the purposes of testing the precision of a stopwatch class, what we need is a function whose execution time is relatively consistent and can be estimated. Here are a few approaches:

1. Controlled Loop Execution

A simple loop with a large number of iterations can provide a relatively consistent execution time. The idea is to perform a simple operation many times:

Function ControlledLoop(iterations As Long)
    Dim i As Long
    For i = 1 To iterations
        ' Simple operation
    Next i
End Function

You can calibrate iterations to a number that gives you a measurable amount of time (e.g., a few milliseconds to seconds). The actual duration will depend on the system and VBA’s execution speed.

2. Fixed Time Delay

Using VBA’s Application.Wait or Sleep function in Windows API, you can create a delay that is relatively consistent:

Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)

Function FixedTimeDelay(milliseconds As Long)
    Sleep milliseconds
End Function

This method will create a delay of a fixed duration. The precision of Sleep is generally adequate for testing, but it’s not perfect due to how Windows handles process scheduling.

3. Combination Approach

You can combine both methods - a controlled loop followed by a fixed time delay. This way, you can measure the overhead of loop execution plus a known delay:

Function CombinedMethod(iterations As Long, delayMilliseconds As Long)
    ControlledLoop iterations
    FixedTimeDelay delayMilliseconds
End Function

Testing the Stopwatch

To test your stopwatch, run the function and measure the time taken:

Function TestStopwatchPrecision()
    Dim sw As New Stopwatch
    Dim iterations As Long, delayMilliseconds As Long
    Dim measuredTime As Double

    iterations = 1000000       ' Adjust based on system performance
    delayMilliseconds = 1000   ' 1-second delay

    sw.Start
    CombinedMethod iterations, delayMilliseconds
    sw.Pause

    measuredTime = sw.Elapsed  ' Time measured by the stopwatch in milliseconds

    ' Output the results
    Debug.Print "Measured Time: " & measuredTime & " ms"

End Function

Remember, these methods provide consistency rather than precision. The goal is to have a function where the execution time doesn’t vary wildly between runs, allowing you to assess the relative accuracy of your stopwatch. However, many factors such as CPU load, background processes, and VBA’s own idiosyncrasies can affect the timing.

To achieve this, you can create a VBA subroutine that records the results of each stopwatch run into an Excel worksheet. This subroutine will vary the sleep duration and iterations, then record the expected time, the measured time, and the difference between these two. Here’s how you can set it up:

1. Prepare the Excel Sheet

Create a worksheet with columns labeled: “Sleep Duration (ms)”, “Iterations”, “Expected Time (ms)”, “Measured Time (ms)”, and “Difference (ms)“.

2. VBA Subroutine to Record Data

Create a subroutine in VBA that loops through different combinations of sleep durations and iterations, using the stopwatch to measure the time taken for each combination. Here’s an example:

Sub RecordStopwatchData()
    Dim ws As Worksheet
    Set ws = ThisWorkbook.Sheets("Sheet1")  ' Update with your sheet name
    Dim row As Long
    row = 2  ' Starting from the second row, assuming the first row has headers

    Dim sleepDurations As Variant, iterations As Variant
    sleepDurations = Array(100, 500, 1000)  ' Array of sleep durations in milliseconds
    iterations = Array(10000, 50000, 100000)  ' Array of iteration counts

    Dim i As Long, j As Long
    For i = LBound(sleepDurations) To UBound(sleepDurations)
        For j = LBound(iterations) To UBound(iterations)
            Dim measuredTime As Double
            measuredTime = MeasureTime(sleepDurations(i), iterations(j))

            ' Calculating expected time
            Dim expectedTime As Double
            expectedTime = sleepDurations(i) + (SomeFunctionToEstimateLoopTime(iterations(j)))

            ' Writing data to the worksheet
            ws.Cells(row, 1).Value = sleepDurations(i)
            ws.Cells(row, 2).Value = iterations(j)
            ws.Cells(row, 3).Value = expectedTime
            ws.Cells(row, 4).Value = measuredTime
            ws.Cells(row, 5).Value = measuredTime - expectedTime

            row = row + 1
        Next j
    Next i
End Sub

' Function to measure time using Stopwatch
Function MeasureTime(sleepDuration As Long, iterCount As Long) As Double
    Dim sw As New Stopwatch
    sw.Start
    FixedTimeDelay sleepDuration
    ControlledLoop iterCount
    sw.Pause
    MeasureTime = sw.Elapsed
End Function

' Function to estimate the loop execution time
' This is a placeholder. You will need to calibrate this based on your system performance.
Function SomeFunctionToEstimateLoopTime(iterations As Long) As Double
    ' Placeholder function - returns a rough estimate
    SomeFunctionToEstimateLoopTime = iterations / 10000  ' Example calculation
End Function

3. Data Analysis

After running this subroutine, your Excel sheet will be populated with data. You can then use Excel’s data analysis tools, like charts, pivot tables, or regression analysis, to find correlations between sleep time, iterations, and system performance.

Notes

Calibration Needed: The function SomeFunctionToEstimateLoopTime needs to be calibrated based on the performance of your system. This function should return an estimated time (in milliseconds) that it takes to complete the specified number of iterations.
Sleep Duration and Iterations: The arrays sleepDurations and iterations can be adjusted based on the range of values you want to test.
Sheet Name: Make sure the sheet name in the Set ws = ThisWorkbook.Sheets("Sheet1") line matches the name of your worksheet.

The ControlledLoop function, as suggested earlier, is a simple VBA function designed to perform a consistent and repeatable task within a predictable time frame. The primary purpose of this function in the context of testing the stopwatch is to provide a mechanism to simulate a task with a known duration, which can then be timed using the stopwatch.

Here’s an example of how the ControlledLoop function might be implemented:

Function ControlledLoop(iterations As Long)
    Dim i As Long
    For i = 1 To iterations
        ' Perform a simple operation that takes a measurable amount of time
        ' For example, simple arithmetic or variable assignment
        Dim temp As Double
        temp = Sqr(i)  ' Example operation: calculate the square root of i
    Next i
End Function

In this implementation:

Parameter: iterations - This parameter controls how many times the loop will execute. By adjusting this number, you can control how long the function takes to execute.
Loop: The For...Next loop runs from 1 to the number specified by iterations.
Operation Inside Loop: Inside the loop, a simple operation is performed - in this case, calculating the square root of the loop index i. This operation is chosen because it’s consistent and takes a measurable amount of time. You can replace this with any operation that is more suitable for your testing needs.

The execution time of the ControlledLoop function will primarily depend on the number of iterations. While it’s not perfectly predictable due to various factors like CPU load, system performance, and VBA’s own execution nuances, it should provide a relatively consistent and controllable task for timing purposes in your stopwatch test.

Find the type mismatch bug here Sub RecordStopwatchData() Dim ws As Worksheet Set ws = ThisWorkbook.Sheets(“Sheet1”) ’ Update with your sheet name Dim row As Long row = 2 ’ Starting from the second row, assuming the first row has headers

Dim sleepDurations() As Long, iterations() As Long
sleepDurations = Array(0, 1, 5, 10, 25, 50, 60, 70, 80, 90, 100) ' Array of sleep durations in milliseconds
iterations = Array(100, 200, 400)  ' Array of iteration counts

Dim i As Long, j As Long
For i = LBound(sleepDurations) To UBound(sleepDurations)
    For j = LBound(iterations) To UBound(iterations)
        Dim measuredTime As Double
        measuredTime = MeasureTime(sleepDurations(i), iterations(j))

        ' Calculating expected time
        Dim expectedTime As Double
        expectedTime = iterations(j) * sleepDurations(i)

        ' Writing data to the worksheet
        ws.Cells(row, 1).Value = sleepDurations(i)
        ws.Cells(row, 2).Value = iterations(j)
        ws.Cells(row, 3).Value = expectedTime
        ws.Cells(row, 4).Value = measuredTime
        ws.Cells(row, 5).Value = measuredTime - expectedTime

        row = row + 1
    Next j
Next i

End Sub

’ Function to measure time using Stopwatch Function MeasureTime(sleepDuration As Long, iterCount As Long) As Double Dim sw As New Stopwatch sw.start ‘FixedTimeDelay sleepDuration ‘ControlledLoop iterCount Call DummyTask(iterCount, sleepDuration) sw.Pause MeasureTime = sw.Elapsed End Function

The code you’ve provided looks well-structured, but the potential for a type mismatch error could arise in the MeasureTime function, specifically in the call to DummyTask(iterCount, sleepDuration). This depends on the implementation of DummyTask. If the parameters expected by DummyTask don’t match the types or order of iterCount and sleepDuration, a type mismatch error could occur.

Here’s a breakdown of potential issues:

Check the DummyTask Function’s Signature: Ensure that DummyTask is expecting two parameters, the first one being an integer (or long) for iteration count and the second one being a long (or integer) for sleep duration. The error might be because of a mismatch in the expected data types or the order of parameters.
Data Types of Arrays: In VBA, when you use Array function, it creates an array of Variant type. This shouldn’t cause a type mismatch error when passing elements to a function expecting Long, but it’s worth keeping in mind, especially if DummyTask has specific parameter type requirements.
Parameter Types in MeasureTime and DummyTask: Ensure that the types of sleepDuration and iterCount in MeasureTime match the expected types in DummyTask. For instance, if DummyTask expects sleepDuration as a Double, but sleepDuration is passed as a Long, it might cause a mismatch.
Uncomment Necessary Function Calls: I noticed that FixedTimeDelay sleepDuration and ControlledLoop iterCount are commented out in MeasureTime. If these are part of the intended functionality, ensure they are uncommented and correctly implemented.
Usage of Call Keyword: In VBA, the Call keyword is optional. You can call DummyTask simply as DummyTask(iterCount, sleepDuration) without the Call. This isn’t likely the source of a type mismatch error, but it’s a note on VBA syntax.

If none of these points resolve the issue, please provide the implementation of DummyTask or any other relevant parts of the code, as the mismatch might be occurring due to the specifics within those functions.

To create an array of Long in VBA instead of an array of Variant, you should explicitly declare the array with its type and then populate it with values. In VBA, when you use the Array function, it indeed creates an array of Variant type by default. To create a typed array, you need to assign the values to each element individually or use a different approach to populate the array. Here’s how you can modify the sleepDurations and iterations arrays in your RecordStopwatchData subroutine:

Sub RecordStopwatchData()
    Dim ws As Worksheet
    Set ws = ThisWorkbook.Sheets("Sheet1")  ' Update with your sheet name
    Dim row As Long
    row = 2  ' Starting from the second row, assuming the first row has headers

    ' Declare arrays of Long
    Dim sleepDurations(10) As Long
    Dim iterations(2) As Long

    ' Populate the sleepDurations array
    sleepDurations = Array(0, 1, 5, 10, 25, 50, 60, 70, 80, 90, 100) ' Array of sleep durations in milliseconds

    ' Populate the iterations array
    iterations = Array(100, 200, 400)  ' Array of iteration counts

    Dim i As Long, j As Long
    For i = LBound(sleepDurations) To UBound(sleepDurations)
        For j = LBound(iterations) To UBound(iterations)
            Dim measuredTime As Double
            measuredTime = MeasureTime(sleepDurations(i), iterations(j))

            ' Calculating expected time
            Dim expectedTime As Double
            expectedTime = iterations(j) * sleepDurations(i)

            ' Writing data to the worksheet
            ws.Cells(row, 1).Value = sleepDurations(i)
            ws.Cells(row, 2).Value = iterations(j)
            ws.Cells(row, 3).Value = expectedTime
            ws.Cells(row, 4).Value = measuredTime
            ws.Cells(row, 5).Value = measuredTime - expectedTime

            row = row + 1
        Next j
    Next i
End Sub

' Rest of your code...

In this code:

I declared sleepDurations and iterations as arrays of Long with predefined sizes.
I then used the Array function to populate them. Note that VBA will automatically convert the values to Long as per the array type during assignment.

This approach ensures that sleepDurations and iterations are indeed arrays of Long and not Variant. This should help avoid any type mismatch errors related to these arrays.

You’re right. In VBA, you can’t directly assign an array created with the Array function to an explicitly typed array like an array of Long. Instead, you have to manually assign each value to the array. Here’s how you can adjust the sleepDurations and iterations arrays:

Sub RecordStopwatchData()
    Dim ws As Worksheet
    Set ws = ThisWorkbook.Sheets("Sheet1")  ' Update with your sheet name
    Dim row As Long
    row = 2  ' Starting from the second row, assuming the first row has headers

    ' Declare arrays of Long and define their size
    Dim sleepDurations(10) As Long, iterations(2) As Long

    ' Manually populate the sleepDurations array
    sleepDurations(0) = 0
    sleepDurations(1) = 1
    sleepDurations(2) = 5
    sleepDurations(3) = 10
    sleepDurations(4) = 25
    sleepDurations(5) = 50
    sleepDurations(6) = 60
    sleepDurations(7) = 70
    sleepDurations(8) = 80
    sleepDurations(9) = 90
    sleepDurations(10) = 100

    ' Manually populate the iterations array
    iterations(0) = 100
    iterations(1) = 200
    iterations(2) = 400

    Dim i As Long, j As Long
    For i = LBound(sleepDurations) To UBound(sleepDurations)
        For j = LBound(iterations) To UBound(iterations)
            Dim measuredTime As Double
            measuredTime = MeasureTime(sleepDurations(i), iterations(j))

            ' Calculating expected time
            Dim expectedTime As Double
            expectedTime = iterations(j) * sleepDurations(i)

            ' Writing data to the worksheet
            ws.Cells(row, 1).Value = sleepDurations(i)
            ws.Cells(row, 2).Value = iterations(j)
            ws.Cells(row, 3).Value = expectedTime
            ws.Cells(row, 4).Value = measuredTime
            ws.Cells(row, 5).Value = measuredTime - expectedTime

            row = row + 1
        Next j
    Next i
End Sub

' Rest of your code...

In this code:

Each element of the sleepDurations and iterations arrays is assigned individually.
This method avoids the “Can’t assign to array” error you encountered.

The arrays are now correctly populated with Long integers, and the rest of the subroutine proceeds to use these arrays as before.

The behavior you’re experiencing with the VBA Sleep function snapping to intervals like 15, 30, 60ms is likely due to the granularity and precision of the Windows timer used by the Sleep function. Windows operating systems typically have a default timer resolution of about 15-16 milliseconds, which means that any sleep time less than this interval might be rounded up to the nearest interval of the system timer’s resolution.

While the exact behavior can vary depending on the version of Windows and system settings, this is a commonly observed characteristic of the Sleep function in Windows. It’s important to note that the Sleep function is designed to pause the execution for at least the specified duration, but the exact wake-up time is not guaranteed and can be longer than requested, especially if the system is under heavy load or if other processes are prioritized by the system scheduler.

For tasks requiring more precise timing, other methods or APIs may need to be considered, such as multimedia timers or high-resolution timers offered by specific Windows APIs. However, these methods are more complex and may require additional considerations for accurate and consistent results.

Yes, there are alternative multimedia timers and high-resolution timers in Windows that can offer more precise timing than the standard Sleep function. These are particularly useful in scenarios where you require higher precision and accuracy. Here are a couple of alternatives:

1. timeSetEvent (Windows Multimedia Timer)

This function from the Windows Multimedia API (winmm.dll) can be used to set up a high-resolution timer.
It allows you to specify a callback function that gets called at specified intervals.
It’s more precise than the standard Sleep function but requires more setup and handling of a callback function.

2. QueryPerformanceCounter and QueryPerformanceFrequency

These functions, which you’ve already seen in the stopwatch example, provide a high-resolution timer.
QueryPerformanceCounter gives you a high-resolution timestamp, and QueryPerformanceFrequency tells you the frequency of the counter.
By using these two in conjunction, you can measure very precise time intervals.

3. CreateWaitableTimer (Windows API)

A more advanced option, CreateWaitableTimer is a Windows API function that creates a waitable timer object that can be set to signal after a specified time.
This can be used for high-precision timing but involves more complex handling of Windows objects and synchronization.

Example of Using timeSetEvent:

Here’s an example of how you might declare and use timeSetEvent in VBA:

Declare Function timeSetEvent Lib "winmm.dll" ( _
    ByVal uDelay As Long, _
    ByVal uResolution As Long, _
    ByVal lpTimeProc As Long, _
    ByVal dwUser As Long, _
    ByVal fuEvent As Long) As Long

' Usage example
' timeSetEvent(time_in_milliseconds, resolution_in_milliseconds, AddressOf MyCallbackFunction, 0, TIME_PERIODIC)

Considerations:

Complexity: These methods are more complex than using Sleep and may require a deeper understanding of Windows API and system-level programming.
Precision vs. Real-time: Even with high-precision timers, real-time guarantees can be hard to achieve in a multitasking operating system like Windows, where the OS scheduler controls the execution of threads.
API Integration: Integrating these APIs into VBA requires declaring and using external functions from system DLLs. This can increase the complexity of your code.

In summary, while there are more precise timers available via Windows APIs, they come with increased complexity and integration challenges. The choice of which timer to use will depend on the specific needs of your application and your comfort level with these more advanced programming concepts.

For macOS, a good alternative to QueryPerformanceCounter for high-resolution timing is to use mach_absolute_time, which is part of the Mach kernel API. This function provides a high-resolution timer that is more precise than standard timing functions available in macOS.

Here is an example of how you could use mach_absolute_time in a macOS environment, typically in a language like C or Objective-C, as VBA does not run natively on macOS:

#include <mach/mach_time.h>

uint64_t start = mach_absolute_time();

// ... your code ...

uint64_t end = mach_absolute_time();
uint64_t elapsed = end - start;

mach_timebase_info_data_t info;
mach_timebase_info(&info);

double elapsedMs = (elapsed * info.numer) / (info.denom * 1e6);

In this code:

mach_absolute_time is called before and after the code block you want to time. This function returns a timestamp based on the number of ticks since the system booted.
mach_timebase_info is used to convert the elapsed ticks into nanoseconds. The Mach time units are converted to nanoseconds using the numer and denom fields from the mach_timebase_info_data_t structure, and then to milliseconds.

For integrating such functionality in an environment where VBA is used (like Excel on macOS), you would typically need to use AppleScript or a macOS-compatible programming language like Swift or Objective-C, and find a way to interface it with your VBA or Office application, which could be quite complex.

Remember, direct integration of such system-level APIs in VBA for macOS is not straightforward due to the differences in the operating system and the programming environment. You may need to consider a hybrid approach or a different toolset if high-precision timing is critical for your application on macOS.

Using mach_absolute_time directly in AppleScript is not straightforward, as AppleScript does not natively support such low-level system calls. However, you can achieve high-precision timing in AppleScript by executing a shell script or a compiled program that uses mach_absolute_time.

Approach 1: Shell Script with Embedded C Code

Write a small C program that uses mach_absolute_time and compile it to create an executable.
Call this executable from AppleScript using the do shell script command.

Example C Code (Save as `timer.c`):

#include <mach/mach_time.h>
#include <stdio.h>

int main() {
    uint64_t time = mach_absolute_time();
    printf("%llu\n", time);
    return 0;
}

Compile the C Program:

Run the following command in Terminal to compile the C program:

gcc -o timer timer.c

AppleScript to Call the Executable:

set startTime to do shell script "/path/to/timer"
-- Your code here
set endTime to do shell script "/path/to/timer"

-- Calculate elapsed time
set elapsedTime to endTime - startTime
display dialog "Elapsed Time: " & elapsedTime

Approach 2: Using osascript with Inline C Code

Alternatively, you can use osascript with inline C code. This is more complex and generally not recommended due to potential security risks and the complexity of inline scripting.

Caveats

Security: Executing compiled code or shell scripts from AppleScript can pose security risks, especially with unsigned or unverified executables.
Complexity: This method adds complexity to your AppleScript and may not be ideal for simple scripting tasks.
Portability: The compiled C program must be present on any system where the script runs.

This approach allows you to use high-resolution timers via AppleScript indirectly by leveraging external compiled code or shell scripts. It’s a workaround due to AppleScript’s limitations in directly accessing low-level system APIs like mach_absolute_time.

Implementing a precise sleep function in macOS using a high-performance counter like mach_absolute_time involves creating a mechanism to accurately measure time elapsed and pause execution for the desired duration. Since AppleScript doesn’t support this level of precision natively, you’d typically need to rely on a combination of AppleScript and a compiled language like C or Swift.

The basic idea is to write a C program that uses mach_absolute_time to measure elapsed time and use a loop to check if the desired sleep duration has been reached. Here’s a step-by-step guide on how you can do this:

Step 1: Create a C Program for High-Precision Sleep

Write a C Program that sleeps for a specified duration using mach_absolute_time.
Compile the Program to create an executable.

C Program Example (`HighPrecisionSleep.c`):

#include <mach/mach_time.h>
#include <stdlib.h>

void preciseSleep(double seconds) {
    uint64_t start = mach_absolute_time();

    mach_timebase_info_data_t info;
    mach_timebase_info(&info);

    double elapsed;
    uint64_t end;

    do {
        end = mach_absolute_time();
        elapsed = (end - start) * (double)info.numer / (info.denom * 1e9);
    } while (elapsed < seconds);
}

int main(int argc, char *argv[]) {
    if (argc < 2) {
        return 1;
    }

    double sleepDuration = atof(argv[1]);
    preciseSleep(sleepDuration);
    return 0;
}

Compile the Program:

In the terminal, navigate to the directory containing the C file and run:

gcc -o HighPrecisionSleep HighPrecisionSleep.c

Step 2: Use the Exec

To create a precise sleep function in Windows using the performance counter (QueryPerformanceCounter), you would typically write a function in a language like C or C++ that continuously polls the performance counter until the desired amount of time has elapsed. VBA itself does not provide the level of precision or control needed for such an operation, but you can call an external DLL function from VBA.

Here’s a step-by-step guide to create a precise sleep function using QueryPerformanceCounter in Windows:

Step 1: Write the C/C++ Code

Create a C or C++ Program that uses QueryPerformanceCounter to implement the precise sleep function.

C/C++ Code Example:

#include <windows.h>

void PreciseSleep(double seconds) {
    LARGE_INTEGER start, end, freq;
    QueryPerformanceFrequency(&freq);
    QueryPerformanceCounter(&start);

    double elapsed;
    do {
        QueryPerformanceCounter(&end);
        elapsed = (end.QuadPart - start.QuadPart) / (double)freq.QuadPart;
    } while (elapsed < seconds);
}

BOOL APIENTRY DllMain(HMODULE hModule, DWORD  ul_reason_for_call, LPVOID lpReserved) {
    switch (ul_reason_for_call) {
    case DLL_PROCESS_ATTACH:
    case DLL_THREAD_ATTACH:
    case DLL_THREAD_DETACH:
    case DLL_PROCESS_DETACH:
        break;
    }
    return TRUE;
}

extern "C" __declspec(dllexport) void PreciseSleepWrapper(double seconds) {
    PreciseSleep(seconds);
}

Step 2: Compile as a DLL

Compile this program as a DLL so that it can be called from VBA.

Compile Command Example (

Implementing a precise sleep function in VBA using performance counters like QueryPerformanceCounter is a bit tricky, as VBA itself doesn’t have the built-in capabilities for high-precision waiting or sleeping. However, you can create a workaround by continuously polling the performance counter until a specified duration has elapsed. Here’s how you can do it:

Precise Sleep Function in VBA Using QueryPerformanceCounter

First, ensure you have the declarations for QueryPerformanceCounter and QueryPerformanceFrequency (which you might already have from the stopwatch class):

Private Declare PtrSafe Function QueryPerformanceCounter Lib "kernel32" (lpPerformanceCount As LARGE_INTEGER) As Long
Private Declare PtrSafe Function QueryPerformanceFrequency Lib "kernel32" (lpFrequency As LARGE_INTEGER) As Long

Private Type LARGE_INTEGER
    LowPart As Long
    HighPart As Long
End Type

Private Const BSHIFT_32 = 4294967296# ' 2 ^ 32

Private Function U64Dbl(U64 As LARGE_INTEGER) As Double
    Dim lDbl As Double, hDbl As Double
    lDbl = U64.LowPart
    hDbl = U64.HighPart
    If lDbl < 0 Then lDbl = lDbl + BSHIFT_32
    If hDbl < 0 Then hDbl = hDbl + BSHIFT_32
    U64Dbl = lDbl + BSHIFT_32 * hDbl
End Function

Next, create the precise sleep function:

Public Sub PreciseSleep(Seconds As Double)
    Dim freq As LARGE_INTEGER, start As LARGE_INTEGER, current As LARGE_INTEGER
    QueryPerformanceFrequency freq
    QueryPerformanceCounter start

    Dim elapsed As Double
    Do
        QueryPerformanceCounter current
        elapsed = (U64Dbl(current) - U64Dbl(start)) / U64Dbl(freq)
    Loop While elapsed < Seconds
End Sub

How It Works

QueryPerformanceFrequency: Gets the frequency of the high-resolution performance counter, which is used to convert the counter value to seconds.
QueryPerformanceCounter: Used to get the current value of the counter at the start and during each loop iteration.
Loop: Continuously checks if the elapsed time has reached the specified duration. The duration is calculated by converting the difference between the current counter value and the start counter value to seconds using the counter frequency.

Usage

PreciseSleep 0.5 ' Sleeps for 0.5 seconds (half a second)

Limitations

CPU Usage: This method can be CPU-intensive, as it involves a tight loop continuously polling the performance counter.
Precision: While more precise than the Sleep function, it’s still subject to the limitations of the VBA environment and the system’s multitasking nature.
Blocking: This function will block any other processing until the sleep duration has elapsed.

This is great for Windows. On the Mac this is how we measure time. Use this and reimplement Stopwatch to work for the Mac as well

#If VBA7 Then Public Declare PtrSafe Sub USleep Lib “/usr/lib/libc.dylib” Alias “usleep” (ByVal dwMicroseconds As Long) #Else Public Declare Sub USleep Lib “/usr/lib/libc.dylib” Alias “usleep” (ByVal dwMicroseconds As Long) #End If

Public Sub Sleep(ByVal dwMilliseconds As Long) Const maxMicro As Long = &HFFFFFED8 ‘unsigned &HFFFFFFFF divided by 1000 is not round Const maxMilli As Long = &H418937 ‘unsigned &HFFFFFED8 divided by 1000 Const maxMilliPos As Long = maxMilli \ 2 ‘&H20C49B Const signBit As Long = &H80000000 Const maxMilliNeg As Long = maxMilli Or signBit ’ Do While dwMilliseconds And signBit USleep maxMicro If dwMilliseconds < maxMilliNeg Then dwMilliseconds = (dwMilliseconds Xor signBit) - maxMilli Xor signBit Else dwMilliseconds = dwMilliseconds - maxMilli End If Loop Do While dwMilliseconds > maxMilli USleep maxMicro dwMilliseconds = dwMilliseconds - maxMilli Loop If dwMilliseconds > maxMilliPos Then USleep (dwMilliseconds * 500& Or signBit) * 2& Else USleep dwMilliseconds * 1000& End If End Sub

To reimplement the Stopwatch class for macOS using the timing method you’ve provided, we’ll need to adapt the existing Windows-based stopwatch to use macOS system calls. The USleep function you’ve provided will be useful for implementing a sleep function, but for a high-resolution stopwatch, we’ll need a way to measure elapsed time with high precision.

macOS doesn’t directly support a high-resolution timing function like QueryPerformanceCounter in VBA. But you can approximate a high-resolution timer using standard VBA timing functions, though with lower precision. Here’s a conceptual outline of how you might reimplement the Stopwatch class for macOS in VBA:

1. Basic Structure

Keep the structure of the Stopwatch class similar, but replace the high-resolution Windows-specific parts with macOS-compatible timing.

2. Timer Function

For macOS, you can use Timer function in VBA, which returns a Single representing the number of seconds elapsed since midnight. Note that Timer is less precise than QueryPerformanceCounter.

3. Stopwatch Class for macOS

Here’s a basic outline:

VERSION 1.0 CLASS
BEGIN
  MultiUse = -1  'True
END
Attribute VB_Name = "Stopwatch"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False

Option Explicit

' Private member variables
Private pStart As Double
Private pElapsed As Double
Private pRunning As Boolean

' Initialize the stopwatch
Private Sub Class_Initialize()
    pRunning = False
    pElapsed = 0
    pStart = 0
End Sub

' Start the stopwatch
Public Sub Start()
    If Not pRunning Then
        pStart = Timer
        pRunning = True
    End If
End Sub

' Pause the stopwatch
Public Sub Pause()
    If pRunning Then
        pElapsed = pElapsed + (Timer - pStart)
        pRunning = False
    End If
End Sub

' Reset the stopwatch
Public Sub Reset()
    pElapsed = 0
    pRunning = False
End Sub

' Restart the stopwatch
Public Sub Restart()
    pElapsed = 0
    pStart = Timer
    pRunning = True
End Sub

' Get the elapsed time in seconds
Public Property Get Elapsed() As Double
    If pRunning Then
        Elapsed = pElapsed + (Timer - pStart)
    Else
        Elapsed = pElapsed
    End If
End Property

' Get whether the stopwatch is running
Public Property Get Running() As Boolean
   Running = pRunning
End Property

Notes:

Precision: The Timer function in VBA has a resolution of about 1 second, which is much less precise than QueryPerformanceCounter.
Functionality: The stopwatch will function similarly, providing start, pause, reset, and elapsed time functionalities.

This approach provides a basic stopwatch functionality in macOS using VBA, albeit with less precision than the Windows version. For tasks requiring very high precision, you might need to explore other programming environments or external tools that can offer higher-resolution timing on macOS.

Creating a precise timer on macOS using mach_absolute_time for high-resolution timing requires using a language that can directly interact with macOS system APIs, such as C, C++, Objective-C, or Swift. VBA doesn’t have direct access to such low-level macOS functions.

Here’s how you can create a precise timer using mach_absolute_time in a language like C or Swift, and then potentially call this code from a higher-level language or application:

Using C or C++:

Write a C/C++ Program: Write a program using mach_absolute_time for high-resolution timing.

Example C Code:

#include <mach/mach_time.h>
#include <stdio.h>

int main() {
    uint64_t start, end;
    mach_timebase_info_data_t tb;

    start = mach_absolute_time();
    // Perform your timed operation here
    end = mach_absolute_time();

    mach_timebase_info(&tb);
    uint64_t elapsedNano = (end - start) * tb.numer / tb.denom;
    printf("Elapsed Time: %llu ns\n", elapsedNano);

    return 0;
}

Compile the Program: Compile this program on macOS using a compiler like gcc or clang.
Execute the Program: Run the compiled program to measure the execution time of the operation.

Using Swift:

Create a Swift Program: Use mach_absolute_time in Swift for precise timing.

Example Swift Code:

import Foundation

var start = mach_absolute_time()
// Perform your timed operation here
var end = mach_absolute_time()

var timebase = mach_timebase_info()
mach_timebase_info(&timebase)

let elapsedNano = (end - start) * UInt64(timebase.numer) / UInt64(timebase.denom)
print("Elapsed Time: $elapsedNano) ns")

Compile and Run: Compile and run your Swift program in a macOS environment.

Integrating with Other Environments (like Excel on macOS):

Integrating this high-resolution timer directly into VBA for Excel on macOS is not straightforward, as VBA does not support calling macOS system APIs. However, you can:

Run your C/C++ or Swift program externally and capture its output from VBA using shell commands.
Use AppleScript or Automator in conjunction with your C/C++ or Swift program to interact with Excel on macOS.

Example of Calling from AppleScript:

You can use AppleScript to run the compiled C/C++ or Swift program and get the output. This script can then be called from VBA using the AppleScriptTask function in Excel for Mac.

Caveat:

This approach requires a multi-language and multi-tool solution, as VBA itself does not provide direct access to macOS system-level APIs for high-resolution timing.

To integrate a C++ function from a .dylib into a VBA project on macOS, you’ll first need to declare the external function in your VBA code. Assume your C++ function absolute_time() is compiled into a .dylib and returns an Int64. You can declare this function in VBA and use it to implement a macOS version of the Stopwatch class.

Here’s how you can rewrite the Stopwatch class for macOS using the absolute_time() function:

Step 1: Declare the External Function

In your VBA module, declare the external function at the top:

#If VBA7 Then
    Public Declare PtrSafe Function absolute_time Lib "/path/to/your.dylib" () As LongLong
#Else
    Public Declare Function absolute_time Lib "/path/to/your.dylib" () As Long
#End If

Replace "/path/to/your.dylib" with the actual path to your compiled .dylib file.
If you’re using a 64-bit version of Office, LongLong is used to handle 64-bit integers. For 32-bit versions, use Long.

Step 2: Implement the Stopwatch Class

Now, you can use absolute_time() to measure time intervals:

VERSION 1.0 CLASS
BEGIN
  MultiUse = -1  'True
END
Attribute VB_Name = "Stopwatch"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False

Option Explicit

Private pStart As LongLong
Private pElapsed As Double
Private pRunning As Boolean

Private Function NanoToSeconds(ByVal nano As LongLong) As Double
    NanoToSeconds = nano / 1E9
End Function

Private Sub Class_Initialize()
    pRunning = False
    pElapsed = 0
    pStart = 0
End Sub

Public Sub Start()
    If Not pRunning Then
        pStart = absolute_time()
        pRunning = True
    End If
End Sub

Public Sub Pause()
    If pRunning Then
        pElapsed = pElapsed + NanoToSeconds(absolute_time() - pStart)
        pRunning = False
    End If
End Sub

Public Sub Reset()
    pElapsed = 0
    pRunning = False
End Sub

Public Sub Restart()
    pElapsed = 0
    pStart = absolute_time()
    pRunning = True
End Sub

Public Property Get Elapsed() As Double
    If pRunning Then
        Elapsed = pElapsed + NanoToSeconds(absolute_time() - pStart)
    Else
        Elapsed = pElapsed
    End If
End Property

Public Property Get Running() As Boolean
    Running = pRunning
End Property

In this implementation:

absolute_time() is used to get the current time in nanoseconds.
NanoToSeconds converts nanoseconds to seconds for easier understanding and comparison.
The Start, Pause, Reset, Restart, and Elapsed methods use absolute_time() to measure and compute the elapsed time.

Notes:

Ensure that the .dylib file is correctly referenced and accessible by the VBA environment.
This implementation assumes that absolute_time() is working correctly and returns the current time in nanoseconds since an arbitrary point in time (like system startup).
The precision and accuracy of the Stopwatch will depend on the implementation of absolute_time() in the .dylib.

In VBA on macOS, loading a dynamic library (.dylib) directly is not as straightforward as it is on Windows, where you can use Declare statements to link to functions in DLLs. macOS does not support this kind of direct linking in VBA. Therefore, you need a workaround to use functions from a .dylib in your VBA project.

There are a few approaches to consider:

1. AppleScript or Automator

You can use AppleScript or Automator to interact with the .dylib. This approach involves writing an AppleScript that calls a shell script or a command-line program which in turn uses the functions from the .dylib. You can then call this AppleScript from VBA.

AppleScript Example: Write an AppleScript that calls a shell script which uses your .dylib. Then, use AppleScriptTask in VBA to execute this AppleScript.

VBA Example:

Sub CallAppleScript()
    Dim scriptOutput As String
    scriptOutput = AppleScriptTask("YourAppleScript.scpt", "YourHandler", "")
End Sub

2. Shell Scripting

Use a shell script to interface with your .dylib. You can call this script directly from VBA using the shell command or do shell script in AppleScript.

Shell Script Example: Create a shell script that calls a C++ executable linked with your .dylib.

VBA Example:

Sub CallShellScript()
    Dim scriptOutput As String
    scriptOutput = MacScript("do shell script ""/path/to/your/script.sh""")
End Sub

3. External Application

Develop a small external application in a language that can load the .dylib (like C, C++, Objective-C, or Swift). This application would perform the necessary operations and communicate the results back to your VBA code, possibly through file I/O, command line outputs, or other inter-process communication methods.

4. Python or Other Scripting Languages

If Python or another scripting language is installed on the user’s machine, you might write a Python script that calls the functions in the .dylib and returns the results. Then, you can execute this script from VBA.

Python Script Example: A Python script that uses ctypes or a similar library to load the .dylib and call its functions.

VBA Example:

Sub CallPythonScript()
    Dim scriptOutput As String
    scriptOutput = MacScript("do shell script ""python3 /path/to/your/script.py""")
End Sub

Note:

These methods add complexity and dependencies on external scripts or applications.
Direct integration of .dylib in VBA for macOS is limited due to the VBA environment’s constraints.
Always ensure that any external scripts or applications you run are secure and from trusted sources to avoid security risks.

As of my last update in April 2023, Excel for Mac does support loading .dylib libraries, but this functionality is somewhat limited compared to the capabilities available on Windows with DLLs. The Declare statement in VBA for Mac can be used to call functions from a .dylib, much like how it’s used for DLLs in Windows. However, there are a few key points to consider:

Library Location: The .dylib should be placed in a location accessible by Excel. It’s often a good practice to place the .dylib in the same directory as your Excel workbook or in a standard library directory.
Function Declaration: The functions in the .dylib need to be declared correctly in your VBA code. The declaration syntax is similar to that used for DLLs in Windows.
Calling Convention: Ensure that the calling conventions and data types in your .dylib functions match those expected by VBA. For instance, data types like Long, String, and others must be correctly handled.
64-bit vs 32-bit: Be mindful of the bitness of your Office installation (64-bit vs 32-bit) as this affects how you declare your functions (PtrSafe attribute and data types like LongPtr).
Error Handling: Be prepared to handle errors, as issues with loading libraries or calling functions can lead to crashes or unexpected behavior in Excel.

Given these considerations, here’s how you might adjust the declaration in VBA to use the absolute_time function from a .dylib:

#If VBA7 Then
    Public Declare PtrSafe Function absolute_time Lib "/path/to/your.dylib" () As LongLong
#Else
    Public Declare Function absolute_time Lib "/path/to/your.dylib" () As Long
#End If

Replace "/path/to/your.dylib" with the actual path to your .dylib file. The function can then be used in your VBA code as shown in the previous example of the Stopwatch class.

Always test your implementation thoroughly, as integrating external libraries can introduce complexities, especially regarding data types and memory management.