API Usage Examples

Code Examples. More...

Code Examples.

Example illustrating a simple svn initialize/finalize cycle for gms client

/* SVC handle which will be populated by GMS client */  
static ClGmsHandleT   handle = 0;

/* Current version supported by gms */
static ClVersionT  correct_version = {'B',1,1};

/* Callbacks to be provided by user. Since we are using any of
 * these functionality here, we will set all of them to NULL
 */
static ClGmsCallbacksT callbacks = {
      .clGmsClusterTrackCallback      = NULL,
      .clGmsClusterMemberGetCallback  = NULL,
      .clGmsGroupTrackCallback        = NULL,
      .clGmsGroupMemberGetCallback    = NULL
};


ClRcT simple_init_finalize_cycle()
{
     ClRcT   rc = CL_OK;

     /* Calling gms intialize with proper values */
     rc = clGmsInitialize(&handle, &callbacks, &correct_version);
     if (rc != CL_OK)
     {
        printf("GMS Initialize failed with rc [0x%x]\n",rc);
        return rc;
     }

     /* Calling finalize on the handle */
     rc = clGmsFinalize(handle);
     if (rc != CL_OK)
     {
        printf("GMS finalize failed with rc [0x%x]\n",rc);
        return rc;
     }

     return CL_OK;
}

Example showing cluster track and track stop functionality

/* SVC handle which will be populated by GMS client */
static ClHandleT   handle = 0;

/* Current version supported by gms */
static ClVersionT  correct_version = {'B',1,1};

/* Callbacks to be provided by user. Since we are using any of
 * these functionality here, we will set all of them to NULL
 */

/* Flag to indicate whether callback was invoked or not */
static ClBoolT     callback_invoked = CL_FALSE;

static void clGmsClusterTrackCallbackFuntion (
        CL_IN const ClGmsClusterNotificationBufferT *notificationBuffer,
        CL_IN ClUint32T             numberOfMembers,
        CL_IN ClRcT                 rc)
{
    callback_invoked = CL_TRUE;
    printf("Inside cluster track callback function. \n");
}

static ClGmsCallbacksT callbacks_non_null = {
    .clGmsClusterTrackCallback      = clGmsClusterTrackCallbackFuntion,
    .clGmsClusterMemberGetCallback  = NULL,
    .clGmsGroupTrackCallback        = NULL,
    .clGmsGroupMemberGetCallback    = NULL
};


ClRcT track_changes_and_changes_only_flag_test()
{
    ClRcT       rc = CL_OK;

    /* Initialize svc client handle */
    rc = clGmsInitialize(&handle,&callbacks_non_null,&correct_version);
    if (rc != CL_OK)
    {
        printf("GMS Initialize failed with rc 0x%x\n",rc);
        return rc;
    }
        
    /* Set the flag to false before triggering the event */
    callback_invoked = CL_FALSE;

    /* Register for cluster track */
    rc = clGmsClusterTrack(handle,CL_GMS_TRACK_CHANGES,NULL);
    if (rc != CL_OK)
    {
        printf("GMS cluster track failed with rc 0x%x\n",rc);
        return rc;
    }


    /* NOTE: In the below wait period, bring down a node or bringup a node 
    *  in the cluster. This will trigger the invocation of the callback.*/
    /* Wait and see if the callback is called */
    sleep(10);

    if (callback_invoked != CL_TRUE)
    {
        printf("Cluster track callback is not invoked\n");
        return CL_OK;
    }

    callback_invoked = CL_FALSE;

    /* Now change the flag to TRACK_CHANGES_ONLY flag */
    rc = clGmsClusterTrack(handle,CL_GMS_TRACK_CHANGES_ONLY,NULL);
    if (rc != CL_OK)
    {
        printf("clGmsClusterTrack with TRACK_CHANGES_ONLY flag failed with "
               "rc = 0x%x",rc);
        return rc;
    }

    /* Trigger an event by killing a node or bringing up another node
     * in the cluster */
    sleep(10);

    if (callback_invoked != CL_TRUE)
    {
        printf("Cluster track callback is not invoked\n");
        return CL_OK;
    }

    /* Track stop */
    rc = clGmsClusterTrackStop(handle);
    if (rc != CL_OK)
    {
        printf("clGmsClusterTrackStop failed with rc = 0x%x",rc);
        return rc;
    }

    /* Finalize */
    rc = clGmsFinalize(handle);
    if (rc != CL_OK)
    {
        printf("finalize failed with rc = 0x%x",rc);
        return rc;
    }
}