INFO: MAPI_NO_COINIT Flag To Make MAPIInitialize Not Call CoInit

• Microsoft Exchange Server, version 5.5 SP1
• Extended Messaging Application Programming Interface (MAPI), version 1.0

SUMMARY

If CoInitializeEx is called with the COINIT_MULTITHREADED flag before MAPIInitialize is called, you will get error 0x80010106 (E_INVALID_FLAGS or RPC_E_CHANGED_MODE). To prevent this error, set MAPI_NO_COINIT (value of 0x8) in the ulFlags member of the MAPIINIT_0 structure passed in MAPIInitialize.

Please note the COINIT_MULTITHREADED flag was added to MAPI in Exchange 5.5 SP1.

MORE INFORMATION

MAPI, by default, will try to initialize COM with a call to CoInitialize. This initializes COM with a single threaded apartment model. Since COM has already been initialized with a multithreaded model and the threading model cannot be changed, MAPIInitialize will fail and return RPC_E_CHANGED_MODE.

If a MAPIINIT_0 structure is passed into MAPIInitialize with ulFlags set to MAPI_NO_COINIT, MAPI will assume that COM has already been initialized and bypass the call to CoInitialize.

As stated before, this flag was added to MAPI in Exchange 5.5 SP1. Attempting to set this flag on earlier versions of MAPI will result in MAPI_E_UNKNOWN_FLAGS, as this flag is not known to previous versions of MAPI.

Steps to Reproduce Behavior

   //Link in MAPI32.LIB to build this code.
   #define _WIN32_DCOM
   #include <stdio.h>
   #include <conio.h>
   #include <mapix.h>

struct StartOle {
StartOle() { 
      CoInitializeEx(NULL,
         COINIT_MULTITHREADED); 
   }
   ~StartOle() { 
      CoUninitialize(); 
   }
} _inst_StartOle;

   #define MAPI_NO_COINIT 8

void main()
{
   HRESULT hRes;

   MAPIINIT_0 MAPIInit;
   MAPIInit.ulFlags = 
//      MAPI_NO_COINIT | 
      0;
   MAPIInit.ulVersion = MAPI_INIT_VERSION;
   hRes = MAPIInitialize(&MAPIInit);

   MAPIUninitialize();
   if (FAILED(hRes))
   {
      printf("Failed with hRes of %x\n",hRes);		
   }
   printf("Hit any key to continue\n");
   while(!_kbhit()){ Sleep(500);};
	
} 

REFERENCES

For additional information about a related fix, please click the article number below in the Microsoft Knowledge Base:

Q179116 FIX: MAPIInitialize() Fails with MAPI_E_INVALID_FLAGS

Additional query words:

Keywords : kbXchge550 kbMAPI kbMsg kbVC kbGrpMsg kbDSupport
Version : WINDOWS:1.0; winnt:5.5 SP1
Platform : WINDOWS winnt
Issue type : kbinfo