[AccessD] Public Variables - Scope and Lifetime

Agreed... My two cents worth says every function or class should manage
their errors; macros should not be used (very very rarely) then only a hard
down can stop the application. At that point the loss of global variables is
moot.

Jim 

-----Original Message-----
From: accessd-bounces at databaseadvisors.com
[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of DWUTKA at marlow.com
Sent: November 28, 2005 11:06 AM
To: accessd at databaseadvisors.com
Subject: Re: [AccessD] Public Variables - Scope and Lifetime

No.  Handled errors do not clear global variables.  Unhandled errors where
the user clicks 'end' will clear ALL variables.

Drew

-----Original Message-----
From: Hale, Jim [mailto:Jim.Hale at fleetpride.com]
Sent: Monday, November 28, 2005 8:49 AM
To: 'Access Developers discussion and problem solving'
Subject: Re: [AccessD] Public Variables - Scope and Lifetime


In this context what does division by zero do? (ie on error resume next;
x=x/0; ) Does it have the same effect as an End? As I recall (but this was
from a discussion looong ago) all globals are cleared with this error.
Jim Hale

-----Original Message-----
From: DWUTKA at marlow.com [mailto:DWUTKA at marlow.com]
Sent: Saturday, November 26, 2005 11:32 PM
To: accessd at databaseadvisors.com
Subject: Re: [AccessD] Public Variables - Scope and Lifetime


Change the stop to an End.  Stop only 'pauses' the code, it doesn't stop
it's execution.  End clears the value, just as it would with a global
variable.

Drew

	-----Original Message-----
	From:	Arthur Fuller [SMTP:artful at rogers.com]
	Sent:	Saturday, November 26, 2005 3:46 PM
	To:	'Access Developers discussion and problem solving'
	Subject:	Re: [AccessD] Public Variables - Scope and Lifetime

	Your reply made me decide to test static functions against a STOP,
which I
	have never done before.
	Turns out that static values are preserved despite a STOP. Code
follows. 
	Place this in a new module:
	<code>
	Static Function CurrentValue(Optional lngNew As Long) As Long

	    Dim lngCurrent As Long
	    On Error GoTo CurrentValue_Error

	    If lngNew <> 0 Then lngCurrent = lngNew
	    CurrentValue = lngCurrent
	    #If conDebug = 1 Then
	        Debug.Print "Current Value: ", CurrentValue
	    #End If

	    On Error GoTo 0
	    Exit Function

	CurrentValue_Error:
	    MsgBox "Error " & Err.Number & " (" & Err.Description & ")" &
vbCrLf & _
	    "in procedure CurrentValue of Module CurrentValues"

	End Function</code>
	Place this in a new module:
	<code>
	Option Compare Database
	Option Explicit

	Sub TestPersistence()
	    CurrentValue (123)
	    MsgBox "Current value is: " & CurrentValue(), vbInformation +
vbOKOnly,
	"Test Persistence of Static Values"
	    Stop
	    MsgBox "Current value is: " & CurrentValue()
	End Sub
	</code>
	Compile, then run the sub above. At the STOP, hit F5 to continue.
The moral
	of the story is that if you want values to persist beyond a STOP,
use static
	functions.
	Arthur
	-----Original Message-----
	From: accessd-bounces at databaseadvisors.com
	[mailto:accessd-bounces at databaseadvisors.com] On Behalf Of
DWUTKA at marlow.com
	Sent: November 26, 2005 1:42 PM
	To: accessd at databaseadvisors.com
	Subject: Re: [AccessD] Public Variables - Scope and Lifetime

	Ugh....not this again!  LOL.  Marty, that is not what happens.  If
you STOP
	your code, then everything gets reset.  That does include your
global
	variables.  It's not a maybe, and they don't 'lose' their values,
the code
	is stopped.  It is just like stopping an .exe, all values in memory
are
	cleared.  The difference is, with Access, that the Access Shell
didn't stop,
	and as soon as you do something requiring code, Access starts it all
up
	again, and so your Globals will be reset.
	It's not a wishy washy thing, it is just how the code works.
	Drew

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