Internal Control Codes

Internal control codes are used exclusively by the Cluster service to notify resource DLLs of certain events. Applications cannot use internal control codes in control code functions.

If you are implementing a resource DLL, you can choose to support any internal control code that indicates an event with implications for your resources. However, note the following behavior:

• Unless otherwise specified in the description of the control code, internal resource control codes are sent to every resource in the cluster. This means your ResourceControl entry point will receive one call for every resource currently supported by your DLL.
• Unless otherwise specified in the description of the control code, internal resource type control codes are sent to every resource type in the cluster. This means your ResourceTypeControl entry point will receive one call for every resource type supported by your DLL.

For example, suppose a resource DLL supports three resource types and is currently managing five resource instances in the cluster. The administrator evicts a node. The resource DLL will receive the CLUSCTL_RESOURCE_TYPE_EVICT_NODE control code three times (one call per resource type) through the ResourceTypeControl entry point, and will receive the CLUSCTL_RESOURCE_EVICT_NODE control code five times (one call per resource instance) through the ResourceControl entry point.