How can I to pass an array to a DLL function?

21 Jul 2006 8:15 PM

Carlos Villaseñor M.

Hi everybody!

I finally have success implementing my first DLL function, I have exported a
C++ function with a DLL using the "Declare" statement in Basic, but now I
have a doubt, how can I to pass an array in the DLL function parameters
list, I need to pass y return the same array, but changed, to my Basic
application.

Below I show my code in Basic:

Private Declare Function CreateDll3 Lib "DLL3.dll" () As Long
Private Declare Sub DestroyDll3 Lib "DLL3.dll" (ByVal objptr As Long)
Private Declare Function GetCpuSpeedDll3 Lib "DLL3.dll" (ByVal objptr As
Long) As Integer

Private Declare Sub valor_prueba Lib "DLL3.dll" (ByVal objptr As Long, ByRef
val())   <--------- this is te function that need to pass an array

Private Declare Sub InitCommonControls Lib "comctl32.dll" ()

Private Sub Form_Initialize()

    InitCommonControls
    ChDir App.Path

End Sub

Private Sub Command1_Click()

    Dim nSpeed As Integer
    Dim s As String
    Dim s2 As String
    Dim objptr As Long
    Dim valor(0 To 3) As Integer

    valor(0) = 3
    valor(1) = 3
    valor(2) = 3

    Screen.MousePointer = vbHourglass
    objptr = CreateDll3()
    nSpeed = GetCpuSpeedDll3(objptr)
    valor_prueba(objptr, valor())   <--------Here I call the DLL function, I
don't know if this is right....

    DestroyDll3 (objptr)
    Screen.MousePointer = 0

    s = nSpeed
    Form1.Text1.Text = "GetCpuSpeedDll3(objptr) returned " + s
    Form1.Text2.Text = "El valor calculado es " + s2

End Sub

I appreciate some help!

Thank you
Carlos Villaseñor

22 Jul 2006 6:23 AM

Michel Posseth [MCP]

Hello carlos

Private Declare Sub valor_prueba Lib "DLL3.dll" (ByVal objptr As Long, ByRef
val()) <--------- there is no declaration type so , you should pass a
array of objects in VB.Net ( in VB6 you would have passed a variant
array )

regards

Michel Posseth

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"Carlos Villaseñor M." <cvmdis***@avantel.net> schreef in bericht
news:uX6hVHQrGHA.4212@TK2MSFTNGP02.phx.gbl...
> Hi everybody!
>
> I finally have success implementing my first DLL function, I have exported
> a
> C++ function with a DLL using the "Declare" statement in Basic, but now I
> have a doubt, how can I to pass an array in the DLL function parameters
> list, I need to pass y return the same array, but changed, to my Basic
> application.
>
> Below I show my code in Basic:
>
> Private Declare Function CreateDll3 Lib "DLL3.dll" () As Long
> Private Declare Sub DestroyDll3 Lib "DLL3.dll" (ByVal objptr As Long)
> Private Declare Function GetCpuSpeedDll3 Lib "DLL3.dll" (ByVal objptr As
> Long) As Integer
>
> Private Declare Sub valor_prueba Lib "DLL3.dll" (ByVal objptr As Long,
> ByRef
> val())   <--------- this is te function that need to pass an array
>
> Private Declare Sub InitCommonControls Lib "comctl32.dll" ()
>
> Private Sub Form_Initialize()
>
>    InitCommonControls
>    ChDir App.Path
>
> End Sub
>
> Private Sub Command1_Click()
>
>    Dim nSpeed As Integer
>    Dim s As String
>    Dim s2 As String
>    Dim objptr As Long
>    Dim valor(0 To 3) As Integer
>
>
>    valor(0) = 3
>    valor(1) = 3
>    valor(2) = 3
>
>    Screen.MousePointer = vbHourglass
>    objptr = CreateDll3()
>    nSpeed = GetCpuSpeedDll3(objptr)
>    valor_prueba(objptr, valor())   <--------Here I call the DLL function,
> I
> don't know if this is right....
>
>
>    DestroyDll3 (objptr)
>    Screen.MousePointer = 0
>
>    s = nSpeed
>    Form1.Text1.Text = "GetCpuSpeedDll3(objptr) returned " + s
>    Form1.Text2.Text = "El valor calculado es " + s2
>
> End Sub
>
>
> I appreciate some help!
>
> Thank you
> Carlos Villaseñor
>
>
>