I'm trying to use a PowerBasic DLL I created with PBDLL 6 in Visual Basic 6.0 SP3. It errors out after calling the DLL function two or three times. The windows error and the VB & PB code is shown below. I would really appreciate some advice.
Thanks, Ron Weber
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Thanks, Ron Weber
Code:
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Windows 98 - 4.10.1998 - error:
This program has performed an illegal operation
and will be shut down.
If the problem persists, contact the program vendor.
VB6 caused an invalid page fault in
module KERNEL32.DLL at 0177:bff7a4a3.
Registers:
EAX=00000018 CS=0177 EIP=bff7a4a3 EFLGS=00010206
EBX=00000002 SS=017f ESP=007fe7f0 EBP=007fe800
ECX=005d0008 DS=017f ESI=005d0000 FS=4b4f
EDX=00000020 ES=017f EDI=005d000c GS=0000
Bytes at CS:EIP:
8b 03 25 fc ff ff 0f 3b 45 0c 0f 83 81 00 00 00
Stack dump:
0000001a 7ff527a8 00000000 881a47df
007fe814 bff88d9b 005d0000 00000020
00000000 007fe86c 7ff314f0 005d0000
00000000 0000001a 7ff31520 7ffdd00c
======================================================
Visual Basic 6.0 - SP3 - Module1.bas:
' DataCenter database record.
Type DataCenterDB
VarTable As String * 6
VarName As String * 100
VarValue As String * 10000
End Type
Declare Function GetVar Lib "DC.DLL" Alias "GETVAR" (ByVal x As String, ByVal y As String, ByVal z As String) As String
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Visual Basic 6.0 - SP3 - frmCreate.bas:
Private Sub cmdGetRecord_Click()
Dim p As String
Dim t As String
Dim n As String
Dim v As String
p = "D:\SIMPLE COMPUTER SOLUTIONS\Software Products\VB 6.0\DataCenter\PowerTree"
t = "IN"
n = "VAR-48884.4"
v = GetVar(p, t, n)
MsgBox v
End Sub
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PBDLL 6 - DC.DLL
#COMPILE DLL
#INCLUDE "*********"
TYPE DataCenterDB
VarTable AS STRING * 6
VarName AS STRING * 100
VarValue AS STRING * 10000
END TYPE
FUNCTION GetVar (BYVAL pname AS STRING, BYVAL t AS STRING, BYVAL n AS STRING) EXPORT AS STRING
ON ERROR GOTO Error_Routine
CLOSE
DIM hFile AS LONG ' data file handle
DIM rec AS DataCenterDB ' data file record
DIM recs AS LONG ' count of records in data file
DIM KeyBlock AS *********** ' index file information
DIM combo AS STRING * 106 ' combined 'Table' and 'DataName'
DIM tout AS LONG
DIM e AS STRING
IF pname <> "" AND RIGHT$(pname,1) <> "\" THEN pname = pname + "\"
' Open the data file
Open_DB:
hFile = FREEFILE
tout = 0
Open_Again:
ERRCLEAR
e = "OPEN"
OPEN pname + "DataCenter.DB" FOR RANDOM LOCK READ WRITE AS hFile LEN = LEN(rec)
e = ""
IF ERR THEN
GetVar = "Error - Unable to open data file DataCenter.DB"
EXIT FUNCTION
END IF
' Get the total number of records in the file and check for sanity.
recs = LOF(hFile) \ LEN(rec)
IF recs * LEN(rec) <> LOF(hFile) THEN
GetVar = "Error - Corrupt data file DataCenter.DB (bad record length)"
EXIT FUNCTION
END IF
' Store Table and Data Name into 'rec' variable.
rec.VarTable = UCASE$(t)
rec.VarName = UCASE$(n)
combo = rec.VarTable + rec.VarName
' Initialize index.
************************
**********************
*****************************************
IF **************** <> 0 THEN
GetVar = "Error - Could not initialize DataCenter.PTX"
EXIT FUNCTION
END IF
' See if Data Name already exists.
********************
' Get record.
IF **************** = 0 THEN
tout = 0
e = "GET"
GET hFile, KeyBlock.RecordNumber, rec
e = ""
GetVar = TRIM$(rec.VarValue)
ELSE
MSGBOX "Variable Not Found"
END IF
****************
CLOSE hFile
EXIT FUNCTION
Error_Routine:
IF e = "OPEN" AND tout < 30000 THEN
tout = tout + 1
RESUME Open_Again
END IF
IF e = "GET" AND tout < 30000 THEN
tout = tout + 1
CLOSE hFile
RESUME Open_DB
END IF
CLOSE
END FUNCTION
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