MS Access(vb6) & DLL Version

Hi Howard,

please have a look into the vb-sample below.
The heaviest thing is the string handling with unicode.
Please have a detailed look into pointers as well.
Important at least where the dll should be (you'll know the difference with paths in win32 and win64).
If you want to use the dll with vba inside MS Access, Excel, … then the dll has to be in the system32- or syswow64-directory (application directory won’t work).
Choosing the dll inside for example a mdb-project via extras -> references won't work 'cause the dll can't be registered without an entry point – so simply copying into system32 or syswow64 … that’s all.

Cheers and welcome here,
Ingo

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my vb-sample - the module1.bas-file...

Attribute VB_Name = "Module1"
Public Declare Function GetPDFfunction1 Lib "QuickPDF.dll" (ByVal Filename As String) As Long
Public Declare Function GetPDFfunction2 Lib "QuickPDF.dll" (ByVal Filename As String, ByVal Opt As Long, ByVal sepa As String, ByVal fipa As Long) As Long
Public Declare Function GetPDFfunction3 Lib "QuickPDF.dll" (ByVal Filename As String, ByVal FieldName As String) As Long

Public Declare Function apiLStrCopyW Lib "kernel32.dll" Alias "lstrcpyW" (ByVal lpString1 As Long, ByVal lpString2 As Long) As Long
Public Declare Function apiLStrLenW Lib "kernel32.dll" Alias "lstrlenW" (ByVal lpString As Long) As Long

Public Function GetStringFromPtrW(ByVal ptr As Long) As String
  'create a matching buffer
  GetStringFromPtrW = String$(apiLStrLenW(ptr), 0)
  'copying the string into the buffer
  apiLStrCopyW StrPtr(GetStringFromPtrW), ptr
End Function

now the relevant functions out of my form1.frm-file...

Private Sub Command1_Click()
    Dim bPfad() As Byte
    Dim sepa() As Byte
    bPfad = StrConv(Text1.Text, vbUnicode)
    sepa = StrConv(";", vbUnicode)
    Text2.Text = GetStringFromPtrW(GetPDFfunction2(bPfad, 2, sepa, 1))
End Sub

Private Sub Command2_Click()
    Dim bPfad() As Byte
    Dim sepa() As Byte
    bPfad = StrConv(Text1.Text, vbUnicode)
    sepa = StrConv(";", vbUnicode)
    Text2.Text = GetStringFromPtrW(GetPDFfunction2(bPfad, 1, sepa, 1))
End Sub

Private Sub Command3_Click()
    Dim bPfad() As Byte
    Dim bfield() As Byte
    bPfad = StrConv(Text1.Text, vbUnicode)
    bfield = StrConv(Text3.Text, vbUnicode)
    Text2.Text = GetStringFromPtrW(GetPDFfunction3(bPfad, bfield)) 'Get...
End Sub

Private Sub option1_Click()
    Dim bPfad() As Byte
    Dim sepa() As Byte
    bPfad = StrConv(Text1.Text, vbUnicode)
    sepa = StrConv(";", vbUnicode)
'   very long string contents will not be supported in a proper way by common edit controls...   
    If Len(GetStringFromPtrW(GetPDFfunction2(bPfad, 3, sepa, 1))) > 2000 Then
      Text2.Text = Left(GetStringFromPtrW(GetPDFfunction2(bPfad, 3, sepa, 1)), 2000) & "...!!!...aborted because not senseful for a single edit-field...!!!"
    Else
      Text2.Text = GetStringFromPtrW(GetPDFfunction2(bPfad, 3, sepa, 1))
    End If
End Sub

Private Sub option2_Click()
    Dim bPfad() As Byte
    bPfad = StrConv(Text1.Text, vbUnicode)
    Text2.Text = GetPDFfunction1(bPfad)
End Sub




Edited by Ingo - 16 Apr 20 at 3:05PM