Stop Statement

Suspends execution.

Syntax

Stop

Remarks

• Execution Suspension: The Stop statement suspends execution but doesn't close any files or clear variables unless it is in a compiled executable (.exe) file.
• Debug Mode: In the development environment, Stop causes the program to enter break mode, allowing you to examine variables, step through code, and use debugging tools.
• Compiled Executable: In a compiled .exe file, Stop acts like the End statement, terminating the program and closing all files.
• Break Mode: When Stop is encountered in the IDE, VB6 pauses execution and highlights the Stop statement, allowing you to inspect the current state.
• Multiple Stop Statements: You can place Stop statements anywhere in your code to create breakpoints for debugging.
• Not for Production: Stop statements should generally be removed before distributing your application, as they can cause unexpected behavior.
• Alternative to Breakpoints: Stop provides a code-based alternative to setting breakpoints in the IDE.
• No Arguments: The Stop statement takes no arguments or parameters.

Common Uses

• Debugging: Pause execution to examine variable values and program state
• Conditional Breakpoints: Combined with If statements for conditional debugging
• Error Investigation: Stop execution when an error condition is detected
• Loop Debugging: Pause execution during specific loop iterations
• Testing: Verify code paths during development

Examples

Simple Stop

Sub Test()
    Dim x As Integer
    x = 10
    Stop  ' Execution pauses here in IDE
    x = x + 5
End Sub

Conditional Stop for Debugging

Sub ProcessData(value As Integer)
    If value < 0 Then
        Stop  ' Pause when invalid data is encountered
    End If
    ' Process value
End Sub

Stop in Loop for Specific Iteration

For i = 1 To 100
    If i = 50 Then
        Stop  ' Pause at iteration 50
    End If
    ProcessItem i
Next i

Stop on Error Condition

Sub CalculateTotal()
    Dim total As Double
    total = GetSubtotal()
    If total < 0 Then
        Stop  ' Investigate negative total
    End If
    SaveTotal total
End Sub

Multiple Stop Statements for Debugging Path

Function ValidateData(data As String) As Boolean
    Stop  ' Entry point
    If Len(data) = 0 Then
        Stop  ' Empty string case
        ValidateData = False
        Exit Function
    End If
    Stop  ' Normal processing
    ValidateData = True
End Function

Stop in Select Case

Select Case userType
    Case 1
        ProcessAdmin
    Case 2
        ProcessUser
    Case Else
        Stop  ' Unknown user type - investigate
End Select

Stop with Error Handler

On Error GoTo ErrorHandler
ProcessData
Exit Sub
ErrorHandler:
    Stop  ' Pause to examine error
    MsgBox Err.Description
End Sub

Stop in Class Module

Private Sub Class_Initialize()
    Stop  ' Verify initialization sequence
    InitializeProperties
End Sub

Stop Before Critical Operation

Sub DeleteAllRecords()
    Stop  ' Verify this operation should proceed
    Dim rs As Recordset
    Set rs = db.OpenRecordset("Data")
    Do While Not rs.EOF
        rs.Delete
        rs.MoveNext
    Loop
End Sub

Stop in Property Procedure

Public Property Let Value(ByVal newValue As Integer)
    If newValue < 0 Then
        Stop  ' Negative value assigned
    End If
    m_Value = newValue
End Property

Stop with DoEvents

For i = 1 To 1000
    DoEvents
    ProcessItem i
    If ShouldDebug Then
        Stop  ' Conditional pause
    End If
Next i

Stop in Event Handler

Private Sub Form_Load()
    Stop  ' Debug form initialization
    InitializeControls
    LoadData
End Sub

Stop with Assert-like Check

Sub ProcessArray(arr() As Integer)
    If UBound(arr) < LBound(arr) Then
        Stop  ' Invalid array bounds
    End If
    For i = LBound(arr) To UBound(arr)
        ProcessItem arr(i)
    Next i
End Sub

Important Notes

• IDE vs. Compiled: Behavior differs between development environment and compiled executables
• Production Code: Remove Stop statements before distributing your application
• Alternative Debugging: Modern IDEs prefer breakpoints over Stop statements
• No File Closure: In IDE, Stop doesn't close files or clear variables
• Break Mode: Allows interactive debugging in the IDE
• End Alternative: In compiled .exe, behaves like the End statement
• Code-Based Breakpoint: Useful when you need a breakpoint that travels with the code
• No Performance Impact: When compiled, can be configured to be removed by compiler

Best Practices

• Use Stop for temporary debugging during development
• Remove Stop statements before final release
• Use meaningful comments explaining why Stop is placed at a location
• Consider using conditional compilation to automatically remove Stop in release builds
• Prefer IDE breakpoints for most debugging scenarios
• Use Stop when you need to share debugging points with team members
• Document any Stop statements that remain for legitimate reasons

Differences from End

• Stop: In IDE, enters break mode; in .exe, terminates program
• End: Always terminates program and closes all files
• Exit: Exits specific procedure/function/loop without terminating program

See Also

• End statement (terminate program)
• Exit statement (exit procedure, function, or loop)
• DoEvents function (yield execution to the operating system)
• Debug.Assert method (conditional debugging)

References

• Stop Statement - Microsoft Docs