Trouble with Double

[E B Knoppert]

I allways get an error using a VB6 callback;

PB6;
DECLARE Sub VBDEBUG ( ByVal ID As Long, Param1 As Double, Param2 As Double, Param3 As Double, Param4 As Double, Param5 As Double )

Global VBCallBack As DWORD

Sub DOVBCALL CDECL ( [ID As Long _
    , Param1 As Double _
    , Param2 As Double _
    , Param3 As Double _
    , Param4 As Double _
    , Param5 As Double _
    ] )

    If Clng( VBCallBack ) = 0 Then Exit Sub

    Call DWORD VBCallBack USING VBDEBUG( ID, PARAM1, PARAM2, PARAM3, PARAM4, PARAM5 )

End Sub

VB6;
Sub MyVBDebug ID As Long _
    , Param1 As Double _
    , Param2 As Double _
    , Param3 As Double _
    , Param4 As Double _
    , Param5 As Double _
    )

'Overflow error (6)

End Sub

If i change the parameters to long, it works fine.
I need doubles.

VB's addressof is used to set the PB's value 'VBCallBack'.
???

[Lance Edmonds]

The PB code shows that you want the compiler to pass the "ID" variable BYVAL and the rest of the parameters BYREF - but the VB code shows all parameters are expected to be passed BYREF.

Did you actually paste this code directly into this message, or did you retype it? I ask simply because the VB code is missing an opening-parenthesis, which could explain the missing BYVAL.

------------------
Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[E B Knoppert]

Sorry, i retyped it.
I tried several methods, all byval , all byref etc..

The error occures only once(!)
When i click a VB button wich activates the callback in PB, VB stops with the error (6).
When i continue i get the msgbox placed in this VBcallback procedure. (test)
When i click this button again, the procedure does not produce an error.
Only when i restart the app (F5).

The weird part is, when i remove the Double parts, it's all ok.
I even tried a type instead of the parameters.

I don't know what's happening, it seems that exchanging the doubles is a problem..

Hope to here an answer on this subject.

My colleague needs a VB debug where he can set variables from within VB in PB.
The calculations are that big that he can't use simple methods like msgbox's etc..

Thanks,



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[Lance Edmonds]

VB error 6 is an overflow error, right?

The PB sub uses CDECL but VB does not call with CDECL, it uses BDECL instead, so your parameter order is effectively reversed when VB passes the parameters to the PB code.

It certainly looks like the problem relates to how you are passing parameters to the PB SUB initially.

Cut & paste all of the relevent code (both VB and PB declares and the SUB prototypes) so we can see *exactly* what you are using, instead of a retyped "summary". Thanks!

------------------
Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[E B Knoppert]

This does work however, in our large app ~370k DLL, an error still occures.(???)
I don't know where to look, i guess i need to strip the app.
We use a lot of string literals.

$IF 0

VB callback example;

Option Explicit

'// c:\pbwork\vbdebug\vbdebug.dll
'ProjectID   : 108
'Project     : VBDebug
'Module      :
'Date pasted : 2000-2-16 / 16-02-2000 14:01:22
Declare Sub SetVBCVALLBACK Lib "C:\PBWORK\VBDEBUG\VBDEBUG.DLL" Alias "SETVBCVALLBACK" (ByVal AddressOfVB As Long)
Declare Sub RunVBCall Lib "C:\PBWORK\VBDEBUG\VBDEBUG.DLL" Alias "RUNVBCALL" ()

Sub VBDEBUG(ByVal ID As Long, Param1 As Double, Param2 As Double, Param3 As Double, Param4 As Double, Param5 As Double)

'    Stop
    MsgBox ID & ", " & Param1 & ", " & Param2 & ", " & Param3 & ", " & Param4 & ", " & Param5

End Sub

Option Explicit

Private Sub Command1_Click()

    SetVBCVALLBACK Val(AddressOf VBDEBUG)
    RunVBCall

End Sub


$ENDIF

DECLARE Sub VBDEBUG ( ByVal ID As Long, Param1 As Double, Param2 As Double, Param3 As Double, Param4 As Double, Param5 As Double )

Global VBCallBack As DWORD

Sub DOVBCALL CDECL ( ParamCount As Long _
   [,ID         As Long _
    , Param1    As Double _
    , Param2    As Double _
    , Param3    As Double _
    , Param4    As Double _
    , Param5    As Double _
    ] )

    Dim pID As Long
    Dim p1 As Double
    Dim p2 As Double
    Dim p3 As Double
    Dim p4 As Double
    Dim p5 As Double

    If Clng( VBCallBack ) = 0 Then Exit Sub

    If ParamCount > 0 Then pID = ID
    If ParamCount > 1 Then P1 = Param1
    If ParamCount > 2 Then P2 = Param2
    If ParamCount > 3 Then P3 = Param3
    If ParamCount > 4 Then P4 = Param4
    If ParamCount > 5 Then P5 = Param5

    Call DWORD VBCallBack USING VBDEBUG( pID, P1, P2, P3, P4, P5 )

    If ParamCount > 0 Then ID     = pID
    If ParamCount > 1 Then Param1 = P1
    If ParamCount > 2 Then Param2 = P2
    If ParamCount > 3 Then Param3 = P3
    If ParamCount > 4 Then Param4 = P4
    If ParamCount > 5 Then Param5 = P5

End Sub

Sub SetVBCVALLBACK( ByVal AddressOfVB As Long ) EXPORT

    VBCallBack = CDWD( AddressOfVB )

End Sub

Sub RunVBCall() EXPORT

    DOVBCALL 0
    DOVBCALL 6, 100, 1, 2, 3, 4, 5

End Sub

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