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Using Methods

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When a client registers with the routing table manager, it can export a set of methods. These methods are used by other clients to obtain client-specific information. Methods enable private communication between clients of the routing table manager.

A client can obtain the list of methods exported by another client. The client calls the RtmGetEntityMethods function, supplying the target client's handle.

Each method exported by a client is uniquely identified by its method identifier. Each client can export up to 32 methods. Each method corresponds to a bit set in the MethodType member of the RTM_ENTITY_EXPORT_METHOD structure. To invoke multiple methods, the client should perform a logical OR of the identifiers for those methods. The syntax and semantics of input and output structures for each protocol must be specified when the protocol is implemented.

Note

Method identifier values that correspond to a bit set in the lower half of the MethodType member (the lower 16 bits) are reserved by Microsoft.

 

To invoke a second client's method, a client calls the RtmInvokeMethod function. The routing table manager arbitrates all requests to invoke a client's methods. The routing table manager performs two functions when it arbitrates between clients:

  • Preventing the second client from invoking a method for a client that is unregistering.
  • Holding an "invoke" request when methods are blocked, and allowing the request to continue when the methods are unblocked.

If a client must prevent other clients from executing its methods, the client can call RtmBlockMethods. The routing table manager will not allow a call to RtmInvokeMethod to be processed until the client unblocks its methods again.

Clients typically block methods when making changes to the private data that is exchanged between clients. Blocking methods is an optional action. A client can also use internal locks to prevent other clients from invoking methods.

For sample code that shows how to use these functions, see Obtain and Call the Exported Methods for a Client.