Help with SetCurrentDirectory in NT

[Ron at OGP]

Hello everyone,

I posted this message some time ago, but got no response...
I really need help on this one, if anybody has
anything to add or information that might help. I'd really appreciate it.

Here's a good one for you bust your development mind on.
I have an application (we'll call this "A") that is creating an instance of another application
("B") through a COM call. My "A" code creates an Object "B" and then is able
to control it correctly using functions and methods exposed by "B".
Program "B" is a bit picky when it is created or destroyed.
It positively has to have the Windows current directory set to its installed directory (we'll call
this "C:\Program Files\B_Prog\") in order for the application to start correctly.
Here is the code I use to do this:


' in the Declarations of the Main Module
public Declare Function GetWindowsDirectory Lib "kernel32" _
Alias "GetWindowsDirectoryA" (byval lpBuffer as string, _
byval nSize as Long) as Long
public Declare Function SetCurrentDirectory Lib "kernel32" _
Alias "SetCurrentDirectoryA" (byval lpPathName as string) as Long

Global BApp as B.Application

' In the Main Section
If FindThisHandle(B_Title) = 0 then
ERRLINE = ERRLINE & Chr$(13) & "Previous B not found"
If Dir(DirStringToSet, vbDirectory) <> "" then
' need to temporaryily set the working directory to the B location for the startup and drivers to load.
ERRLINE = ERRLINE & Chr$(13) & "Correct Directory for working found"
If SetCurrentDirectory("C:\Program Files\B_Prog\") <> 0 then
ERRLINE = ERRLINE & Chr$(13) & "Working Directory set..."
set B_App = CreateObject("B.Application")
ERRLINE = ERRLINE & Chr$(13) & "B OBJECT CREATED"
While BApp.IsInitialized = false
doomtri = doomtri + 1
If doomtri < 19000 then
' Life is good... it should be done.
else
Mess = "Couldn't properly initialize B Program, please start and initialize B first, exit out, and then try to start Program A."

Mess = Mess & Chr$(13) & "A computer re-boot might also necessary. Program A will now exit."
MsgBox Mess, vbCritical
End

End If
Wend
ERRLINE = ERRLINE & Chr$(13) & "Initilzation has taken place... " & doomtri & " Cycles made"
IsBAppStarted = true
dBWin = FindThisHandle(B_Title)
ERRLINE = ERRLINE & Chr$(13) & "set the B indicator tp true."

else

IsBAppStarted = false
ERRLINE = ERRLINE & Chr$(13) & "set the B Indicator to false"
MsgBox "Couldn't Start Program B. Program A will now shutdown.", vbCritical
End
End If






In the Windows 95 or 98(se) environment, the SetCurrentDirectory does its job
and set the windows directory to the right spot allowing me to make a successful
call to the B Program object.
The same deal happens when the time comes to terminate the object.
My colleges and I discovered something disturbingly consistent
in Windows NT and 2000 though.
Through a few code tests, we were able to find that SetCurrentDirectory
will not set the windows
directory desired for an object invoked through COM in the way we
are doing it now. This was confirmed by creating a small COM program to
display "HELLO World!" and
setting the directory beforehand. The GetCurrentDirectory function was
successful but returned "C:\Winnt"... the windows path directory.
My question is:
Has anyone else had a similar problem with these functions when using
COM in the Windows NT or 2000 platform? I suspect it might be a very common problem as we have tried three different
machines and the same deal occurs.

Thanks for any help in advance...



Ron D.
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[Cimperiali]

May be this can apply to your situation:
From Api-guide:
"The SetCurrentDirectory function changes the current directory for the current process."
So, if your Com application runs in a different process due to winnt/win2000, it will not be affected. May be you should repeat the setCurrentDirectory from within the com component.

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The Rater