object_instance_test.cpp

#include <open62541/server.h>
#include <open62541/server_config_default.h>

namespace NodeIds {
	namespace Objects {
		UA_NodeId MyStruct;
	}
	namespace Types {
		namespace MyStruct {
			UA_NodeId root;
			UA_NodeId TimeStamp;
		}
	}
}

int main() {
	UA_Server *server = UA_Server_new();
	UA_ServerConfig *config = UA_Server_getConfig(server);
	UA_ServerConfig_setDefault(config);
	
	UA_StatusCode statusCode;
	
	// Add MyStruct type
	auto typeAttributes = UA_ObjectTypeAttributes_default;
	typeAttributes.displayName = UA_LOCALIZEDTEXT("en", "MyStruct");
	typeAttributes.isAbstract = false;
	statusCode = UA_Server_addObjectTypeNode(
		server,
		UA_NODEID_NULL,
		UA_NODEID_NUMERIC(0, UA_NS0ID_BASEOBJECTTYPE),
		UA_NODEID_NUMERIC(0, UA_NS0ID_HASSUBTYPE),
		UA_QUALIFIEDNAME(1, "t_MyStruct"),
		typeAttributes,
		nullptr,
		&NodeIds::Types::MyStruct::root		
	);
	
	// Add timestamp to MyStruct
	auto timestampAttributes = UA_VariableAttributes_default;
	timestampAttributes.displayName = UA_LOCALIZEDTEXT("en", "TimeStamp");
	timestampAttributes.dataType = UA_TYPES[UA_TYPES_DATETIME].typeId;
	statusCode = UA_Server_addVariableNode(
		server,
		UA_NODEID_NULL,
		NodeIds::Types::MyStruct::root,
		UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT),
		UA_QUALIFIEDNAME(1, "TimeStamp"),
		UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE),
		timestampAttributes,
		nullptr,
		&NodeIds::Types::MyStruct::TimeStamp
	);
	
	// Make timestamp mandatory
	statusCode = UA_Server_addReference(
		server, 
		NodeIds::Types::MyStruct::TimeStamp,
		UA_NODEID_NUMERIC(0, UA_NS0ID_HASMODELLINGRULE),
		UA_EXPANDEDNODEID_NUMERIC(0, UA_NS0ID_MODELLINGRULE_MANDATORY),
		/* isForward: */true
	);
	
	// Add instance of MyStruct under NS0/Objects
	auto objectAttributes = UA_ObjectAttributes_default;
	objectAttributes.displayName = UA_LOCALIZEDTEXT("en", "MyStruct");
	statusCode = UA_Server_addObjectNode(
		server,
		UA_NODEID_NULL,
		UA_NODEID_NUMERIC(0, UA_NS0ID_OBJECTSFOLDER),
		UA_NODEID_NUMERIC(0, UA_NS0ID_ORGANIZES),
		UA_QUALIFIEDNAME(1, "MyStruct"),
		NodeIds::Types::MyStruct::root,
		objectAttributes,
		nullptr,
		&NodeIds::Objects::MyStruct
	);	
	
	// start server
	bool isRunning = true;
	UA_Server_run(server, &isRunning);
}

MODELLINGRULE_MANDATORY was missing for timestamp.
See open62541/open62541#3956