ApiSetGroupDependencyExpression (Opnum 175)

The ApiSetGroupDependencyExpression method<149> instructs the server to set the dependency relationship for the Cluster Group that is identified by hGroup to the complex dependency, as specified in section, using dependency expression represented by lpszDependencyExpression. For successful completion of the method, the server MUST add the dependency information to the nonvolatile cluster state.

Servers MUST maintain complex group dependencies as nonvolatile configuration data in their cluster state.

Dependency expressions are "ANDs" only; "ORs" are not allowed, and parentheticals, "(" and ")", are ignored. Example dependency expressions can be as follows: a and b, a and (b and c), a and b … and n, and so on. The server MUST fail this method with ERROR_INVALID_PARAMETER if the dependency expression contains "ORs". The client MUST provide an input lpszDependencyExpression that conforms to the following grammar:

   | "{" and_expression "}"
   | "{" and_expression "}" "and" and_expression
   | group "and" and_expression
   | "{" and_expression "}" "and" and_expression
     "[" groupID "]"
   | "[" groupName "]"

In this grammar, "groupID" represents the ID of a group, as returned by CLUSCTL_GROUP_GET_ID (section, and "groupName" represents the name of a group, as returned by CLUSCTL_GROUP_GET_NAME (section

The server MUST clear the dependency relationship for hGroup if the null Unicode string (0x0000) is specified.

The server MUST fail this method using ERROR_INVALID_PARAMETER in the following cases:

  • If the dependency expression does not conform to the above grammar.

  • If one of the provider groups depend on hGroup, where a circular dependency would be introduced.

  • If hGroup depends on a provider group set that contains hGroup, where a circular dependency would be introduced.

The server MUST accept an ApiSetGroupDependencyExpression request only if its protocol server state is read/write, as specified in section 3.1.1.

The server MUST require that the access level associated with the hGroup context handle is "All" (section 3.1.4).

 ApiSetGroupDependencyExpresson (
   [ in ] HGROUP_RPC hGroup,
   [ in ] LPCWSTR lpszDependencyExpression,
   [ out ] error_status_t *rpc_status

hGroup: An HGROUP_RPC (section context handle that was obtained in a previous ApiOpenGroup (section, ApiOpenGroupEx (section, or ApiCreateGroup (section method call.

lpszDependencyExpression: A pointer to a null-terminated Unicode string buffer containing a valid dependency expression.

rpc_status: A 32-bit integer used to indicate success or failure. The RPC runtime MUST indicate by writing to this parameter whether the runtime succeeded in executing this method on the server. The encoding of the value passed in this parameter MUST conform to encoding for comm_status and fault_status, as specified in Appendix E of [C706].

Return Values: The method MUST return the following error codes for the specified conditions.

Return value/code







The data that is pointed to by either the hGroup parameter or the hDependsOn parameter does not represent a valid HGROUP_RPC context handle.



An exception occurred in the service when handling the control request.



RPC server is unavailable.



The group represented by the hGroup parameter no longer exists in the nonvolatile cluster state.



The cluster node is shutting down.

For any other condition, this method MUST return a value that is not one of the values listed in the preceding table. The client MUST behave in one consistent, identical manner for all values that are not listed in the preceding table. The client SHOULD treat errors specified in section as recoverable errors, and initiate the reconnect procedure as specified in section