I am using the visual studio express 2005's setting of "register com
interop". does the proper job of registering my Classslib as useable by
native(unmanaged)  com consumer?
Can any one confirm one way or another?

using the com interface from unmanaged application, I don't have any problem
calling functions returning only primitive data types and even strings.

However I am having problem using the assembly from the same native
application through
com interface when there is string array involved.  In the vb project I did
"enable com interop". and use the class library template.

the desired call signature by COM consumer is something like this
integer li_rc, li_sz
string  ls_out[]
string  ls_in

li_rc = myfcn(ls_in , ls_out, li_sz)   / li_sz is to contain the number of
the elements in ls_out
   // only ls_in is to pass by vale, the rest by reference

Vb classlib has something like this

Function myfcn( ByVal sIn As String,  _
        <Out()> <MarshalAs(UnmanagedType.LPArray,
ArraySubType:=UnmanagedType.LPStr, SizeParamIndex:=1)> ByRef sOut As
String(),_
        <Out()> ByRef iCnt As Integer) As Integer
       sOut = Split(sIn, vbTab)
       icnt  =  sOut.GetUpperBound(0) + 1
End Function