4.1 Catalog Session and Capabilities Initialization

Figure 6: Session and capabilities negotiation

The preceding figure shows the sequence for a COMA client (that supports catalog versions 3.00 to 5.00) initializing a session with the COMA server (that supports catalog version 5.00) and determining its capabilities, on behalf of a client application that requested the COMA client to establish a session with the COMA server.

• The COMA client starts by performing DCOM activation for the COMA server object on the server by using the CLSID CLSID_COMAServer.

• The COMA client calls ICatalogSession::InitializeSession (section 3.1.4.5.1) method on the COMA server DCOM object.

   HRESULT
   ICatalogSession::InitializeSession(
       [in] float flVerLower = 3.0,
       [in] float flVerUpper = 5.0,
       [in] long reserved = 0x00000000,
       [out] float* pflVerSession = 
               {pointer to uninitialized memory});
    
  

• The server checks to see if it supports any version in the range 3.0 and 5.0. In this case, it does support version 5.0; thus, it sets the pflVerSession parameter to 5.0 and returns S_OK.

   HRESULT = S_OK
   ICatalogSession::InitializeSession(
       [in] float flVerLower = {unchanged},
       [in] float flVerUpper = {unchanged},
       [in] long reserved = {unchanged},
       [out] float* pflVerSession = 5.0);
    
  

• The COMA client stores the version number of the server and ensures that for further communication with the server it will use the schema for catalog version 5.00.

• The COMA client then tries to determine the capabilities of the server by calling the ICatalogSession::GetServerInformation (section 3.1.4.5.2) method on the COMA server DCOM object.

   HRESULT
   ICatalogSession::GetServerInformation(
       [out] long * plReserved1 = NULL,
       [out] long * plReserved1 = NULL,
       [out] long * plReserved1 = NULL,
       [out] long * plMultiplePartitionSupport = 
               {pointer to uninitialized memory},
       [out] long * plReserved1 = NULL,
       [out] long * plReserved1 = NULL);
    
  

• The COMA server determines if it supports multiple partitions. In this case, it does, so it sets plMultiplePartitionSupport = 0x00000002 and returns S_OK.

   HRESULT = S_OK
   ICatalogSession::GetServerInformation(
       [out] long * plReserved1 = {unchanged},
       [out] long * plReserved1 = {unchanged},
       [out] long * plReserved1 = {unchanged},
       [out] long * plMultiplePartitionSupport = 0x00000002, 
       [out] long * plReserved1 = {unchanged},
       [out] long * plReserved1 = {unchanged});
    
  

• The COMA client now checks to see if the COMA server supports non-native bitness. It does so by calling the ICatalog64BitSupport::SupportsMultipleBitness method on the COMA server DCOM object.

   ICatalog64BitSupport::SupportsMultipleBitness(
       [out] int * pbSupportsMultipleBitness = {pointer to 
       uninitialized memory for the returned bitness value});
    
  

• The COMA server determines whether it supports non-native bitness. In this case, it does not, so it sets pbSupportsMultipleBitness to 0x00000000 and returns S_OK.

   HRESULT = S_OK
       ICatalog64BitSupport::SupportsMultipleBitness(
       [out] int * pbSupportsMultipleBitness = 0x00000000);
    
  

• The COMA client remembers that the server does not support multiple bitnesses.