From: Andrew Wroe <andrew.wroe@...>
Date: 2006-07-13T00:20:13+09:00
Subject: Ruby problems calling VB COM using win32ole

Hi,

I'm experiencing some unusual behaviour trying to use VB COM through 
win32ole in Ruby, and I'm hoping someone might be able to help. I'm 
using Ruby 1.84-19 (final) here.

I've included the contents of the files I'm using to reproduce these 
issues below. Note that you need VB6 to build the COM DLL, but hopefully 
you'll be able to see what it's doing without this.

If you run the script, you'll find that it calls a VB subroutine that 
raises an error, and just before this it displays a dialog window saying 
"About to raise error...". However, despite the script only containing 
one call to this subroutine, when you click OK to dismiss the window it 
appears again. Is this a bug or is there an explanation for it?

The script then calls a VB function that returns an empty variant and an 
uninitialised array in a variant. However, when Ruby tries to display 
the contents of the return value it gives different results, namely 
'nil' and 'false'. I was expecting it to display 'nil' in both cases 
since there is no data available, but perhaps I've misunderstood 
something. Note that until the most recent version, this final call 
would actually generate a segmentation fault!

Thanks,

Andrew.


Problems.rb
___________

require 'win32ole'

def problems()
begin
	test = WIN32OLE.new('Project1.Class1')
	test.raiseerror()
end
rescue
	puts test.emptyvariant()
	puts test.emptyarray()
end

problems()


Class1.cls
__________

VERSION 1.0 CLASS
BEGIN
  MultiUse = -1  'True
  Persistable = 0  'NotPersistable
  DataBindingBehavior = 0  'vbNone
  DataSourceBehavior  = 0  'vbNone
  MTSTransactionMode  = 0  'NotAnMTSObject
END
Attribute VB_Name = "Class1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = True
Option Explicit
Public Function EmptyVariant() As Variant
End Function
Public Function EmptyArray() As Variant
    Dim Test() As Variant
    EmptyArray = Test
End Function
Public Sub RaiseError()
    MsgBox "About to raise error..."
    Err.Raise vbObjectError
End Sub


Project1.vbp
____________

Type=OleDll
Class=Class1; Class1.cls
Reference=*\G{00020430-0000-0000-C000-000000000046}#2.0#0#C:\WINNT\System32\STDOLE2.TLB#OLE 
Automation
Startup="(None)"
ExeName32="Project1.dll"
Command32=""
Name="Project1"
HelpContextID="0"
CompatibleMode="1"
CompatibleEXE32="Project1.dll"
MajorVer=1
MinorVer=0
RevisionVer=0
AutoIncrementVer=0
ServerSupportFiles=0
VersionCompanyName="BNP Paribas"
CompilationType=0
OptimizationType=0
FavorPentiumPro(tm)=0
CodeViewDebugInfo=0
NoAliasing=0
BoundsCheck=0
OverflowCheck=0
FlPointCheck=0
FDIVCheck=0
UnroundedFP=0
StartMode=1
Unattended=0
Retained=0
ThreadPerObject=0
MaxNumberOfThreads=1
ThreadingModel=1

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