Microsoft KB Archive/173649

= PRB: Memory Corruption in VB4-16 When Passing Recordset to Sub =

Article ID: 173649

Article Last Modified on 1/8/2003

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APPLIES TO


 * Microsoft Visual Basic 4.0 Professional Edition

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This article was previously published under Q173649



SYMPTOMS
When passing a recordset to another Sub or Function, you see memory corruption or may experience a general protection fault (GP fault) in Vba5.dll.



CAUSE
The called procedure may be declaring the recordset "As Object" instead of "As Recordset".



RESOLUTION
Change the declaration in the called procedure to "As Recordset".



STATUS
Microsoft is researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.



MORE INFORMATION
Microsoft provides code examples for illustration only, without warranty either expressed or implied, including but not limited to the implied warranties of merchantability and/or fitness for a particular purpose.

This code is provided 'as is' and Microsoft does not guarantee that the following code can be used in all situations. Microsoft does not support modifications of the code to suit customer requirements for a particular purpose.

Steps to Reproduce Behavior
  In Microsoft Access 2.0 or another front-end, create a Jet 2.x database (or use NWIND or BIBLIO) and add the following table:      Table: Table1 Field: K1   Long Field: K2   Long Field: K3   Text (3) Field: Desc Text  Make a composite primary key, consisting of K1, K2, and K3, and then save the table design.  Add the following data:      K1   K2   K3   Desc 1234  22222   abc   xxxxxxxxxxx 1234  22222   def   xxxxxxxxxxx 1234  22222   ghi   xxxxxxxxxxx 1234  22222   jkl   xxxxxxxxxxx  Create a Visual Basic 4.0 16-bit application.</li> Add a command button (Command1) to the form.</li>  Add the following code to the form: option Explicit

Private Sub Command1_Click Dim db As Database, rs As Recordset Set db = DBEngine(0).OpenDatabase _ ("c:\office\access20\sampapps\nwind.mdb") ' alter as needed Set rs = db.OpenRecordset("Table1") rs.Index = "PrimaryKey" Test_Call rs       rs.Close db.Close End Sub

Sub Test_Call(rs As Object) Dim K1 As Long, K2 As Long, K3(3) As String, I As Long K1 = 1234 K2 = 22222 K3(0) = "abc" K3(1) = "def" K3(2) = "ghi" K3(3) = "jkl" Debug.Print "Pass 1" For I = 0 To 3 rs.Seek "=", K1, K2, K3(I) Debug.Print I; K1; K2; K3(0), K3(1), K3(2), K3(3) Next I       Debug.Print "Pass 2" For I = 0 To 3 rs.Seek "=", K1, K2, K3(I) Debug.Print I; K1; K2; K3(0), K3(1), K3(2), K3(3) Next I       Debug.Print "Pass 3" For I = 0 To 3 rs.Seek "=", K1, K2, K3(I) Debug.Print I; K1; K2; K3(0), K3(1), K3(2), K3(3) Next I     End Sub </li> Make sure you change the .OpenDatabase method to correctly point to the database.</li> Run the application and click the command button. You may need to do this several times to see the error.</li></ol>

Result
You should see either intermittent and worsening corruption of variables in the Debug Window, or you may get a GP fault in Vba5.dll.

Workaround
Change "Sub Test_Call (rs As Object)" to "Sub Test_Call(rs As Recordset)".

NOTE: This problem does not appear in Visual Basic 4.0 32-bit.

Additional query words: late-bound late bound vb4

Keywords: kb16bitonly kbprb KB173649

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