#IF #End If

I'm not real familiar with VB6, and in the program I'm working with, it has some conditional statements that begin with a #

#If myVariable <> 1 Then

do something

#End If

What is the purpose of the # sign? How does it make the conditional different from a conditional without the #?

Thanks

The #If statements are not compiled into the program unless the argument is True. Look in MyProject|Properties|Make and in Conditional Compilation Arguments you'll probably find myVariable.

Quote:

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Originally Posted by MartinLiss

The #If statements are not compiled into the program unless the argument is True. Look in MyProject|Properties|Make and in Conditional Compilation Arguments you'll probably find myVariable.

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I see. That would make sense because these statements are checking to see if the user is using an outdated operating system.

Thanks

The statements probably are evaluated upon each run instead of specific compile versions for each OS.

Ps, if you dont have any further questions then dont forget to mark your thread Resolved from the Thread Tools menu. :)

Quote:

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Originally Posted by RobDog888

The statements probably are evaluated upon each run instead of specific compile versions for each OS.

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No, they are included in, or left out of, the program at compile time. If included they behave just like any other If.

Here is official msdn documentation if anyone is interested
#If .. Then .. #Else directive
#Const directive

Quote:

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they are included in, or left out of

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Wasnt quite sure which way you were meaning Martin but this quote kinda cleared it up for me.

Quote:

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Code excluded during conditional compilation is completely omitted from the final executable file, so it has no size or performance effect.

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Thanks, cleared that up for me :)

Now I sure do remember seeing msdn code with os platform conditional directives but it didnt state to complie separate explicit versions of your exe. So then compiling on different OS' is the only way to create OS specific versions of your app? Seems cumbersom and counterproductive.

Quote:

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Originally Posted by RobDog888

So then compiling on different OS' is the only way to create OS specific versions of your app? Seems cumbersom and counterproductive.

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It isn't the only way, those particular conditions are just something they have provided for you - which made a lot of sense back in the NT/95 days if you were publishing code on the web etc.

You can create+set your own conditions in the Project Properties (on the Make tab), and use them in exactly the same way.

Another example of using compilation directives. Let's say I have a commercial ocx that has 2 versions, one is a demo version while the other is a release version. The 2 ocx's are actually one. The conditional [#If DEMO Then] runs and compiles only demo-related code and the [#Else] portion runs and compiles only non-demo related code. One can even condition out entire functions and subroutines, or have yet more fun... Creating functions that have different prototypes depending on the directive.

Code:

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#If DEMO Then
    Private Function HasTrialExceeded(ByVal TrialPeriod As Long) As Boolean
#Else
    Private Function ValidateLicense(ByVal Flags As Long, ByVal hWnd As Long) As Boolean
#End If
  .... code
End Function

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When you use conditional arguments there is one danger and that is forgetting to turn the argument off when you compile for prodution. To avoid that situation I always include the following Sub which prevents compilation if the argument is still on.

Code:

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Public Sub DoNotAllowTestCodeToCompile()
'***************************************************************************
'Purpose: Don't allow the program to compile if Testing = non-zero is set in
'        Project > MessagingWizard Properties > Make
'Inputs:  None
'Outputs: None
'***************************************************************************

    #If Testing Then
        Do not compile
    #End If
   
End Sub

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i place my compilation arguments settings in the Comments property of the Make tab. These are visible in the exe's properties when you right click the exe. As you switch args on and off its not always easy to remember what a particular exe's args was compiled with.