ReDim VB string array

[Bill Cadenhead]

I'm trying to pass a VB string array to PB, enlarge it, write to it, and pass it back to VB. Something's not working. Here's the code --




In VB ------


Private Declare Sub enlarge_string_array _
Lib "m:\Power Basic\Lib\Sorting and Searching\main.dll" _
(s() As String)


===================================================


Private Sub Command1_Click()

Dim s() As String
Dim msg As String
Dim i As Integer



ReDim s(0 To 5)



'goto PB --
Call enlarge_string_array(s())



'show results --
For i = LBound(s) To UBound(s)
msg = msg & i & " -- " & s(i) & Chr(10)
Next

MsgBox msg

End Sub



'=======================================================


In PB -------



SUB enlarge_string_array ALIAS "enlarge_string_array" (pSA AS DWORD) EXPORT

DIM LBound_ AS LONG
DIM UBound_ AS LONG
DIM array_address AS DWORD
DIM ret AS LONG



LBound_ = vbArrayLBound(pSA, 1)
UBound_ = vbArrayUBound(pSA, 1)


array_address = vbArrayFirstElem(pSA)
MSGBOX STR$(array_address)
DIM s(LBound_ TO UBound_) AS STRING AT array_address


'try to redim from (0 ... 5) to (0 ... 10) --
ret = vbArrayRedim(pSA, 11)
IF ret = 0 THEN
MSGBOX "problem with vbArrayRedim"
END IF



MSGBOX "after enlargement" 'OK THRU HERE



s(3) = "new value at #3" 'DOESN'T CAUSE A CRASH 'BUT ASSIGNMENT DOES NOT GET BACK TO VB

MSGBOX "after first assignment"



s(7) = "new value at #7" 'CAUSES VB TO CRASH
MSGBOX "after second assignment"

END SUB

[Peter Jinks]

Hi Bill,

Try this PB code:

SUB enlarge_string_array ALIAS "enlarge_string_array" (pSA AS DWORD) EXPORT

   DIM LBound_ AS LONG
   DIM UBound_ AS LONG
   DIM array_address AS DWORD
   DIM ret AS LONG

   'try to redim from (0 ... 5) to (0 ... 10) --
   ret = vbArrayRedim(pSA, 11)
   IF ret = 0 THEN
   MSGBOX "problem with vbArrayRedim"
   END IF

   LBound_ = vbArrayLBound(pSA, 1)
   UBound_ = vbArrayUBound(pSA, 1)
   array_address = vbArrayFirstElem(pSA)
   
   MSGBOX STR$(LBound_) & " to " & STR$(UBound_) & " at " & STR$(array_address)
   DIM s(LBound_ TO UBound_) AS STRING AT array_address

   MSGBOX "after enlargement" 'OK THRU HERE

   s(3) = "new value at #3" 'DOESN'T CAUSE A CRASH 'BUT ASSIGNMENT DOES NOT GET BACK TO VB

   MSGBOX "after first assignment"

   s(7) = "new value at #7" 'CAUSES VB TO CRASH
   MSGBOX "after second assignment"

END SUB

Your problem is that you DIM s at the size and address of the array, and then redimension it. You need to do those two the other way around! The array will definitely change size and there's no guarantee it will be in the same place in memory either.

Regards,

Pete.

[Bill Cadenhead]

Perfect! Thanks