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- /* This work is licensed under a Creative Commons CCZero 1.0 Universal License.
- * See http://creativecommons.org/publicdomain/zero/1.0/ for more information. */
- /**
- * Working with Variable Types
- * ---------------------------
- *
- * Variable types have three functions:
- *
- * - Constrain the possible data type, value rank and array dimensions of the
- * variables of that type. This allows interface code to be written against
- * the generic type definition, so it is applicable for all instances.
- * - Provide a sensible default value
- * - Enable a semantic interpretation of the variable based on its type
- *
- * In the example of this tutorial, we represent a point in 2D space by an array
- * of double values. The following function adds the corresponding
- * VariableTypeNode to the hierarchy of variable types.
- */
- #include <open62541/plugin/log_stdout.h>
- #include <open62541/server.h>
- #include <open62541/server_config_default.h>
- #include <signal.h>
- #include <stdlib.h>
- static UA_NodeId pointTypeId;
- static void
- addVariableType2DPoint(UA_Server *server) {
- UA_VariableTypeAttributes vtAttr = UA_VariableTypeAttributes_default;
- vtAttr.dataType = UA_TYPES[UA_TYPES_DOUBLE].typeId;
- vtAttr.valueRank = UA_VALUERANK_ONE_DIMENSION;
- UA_UInt32 arrayDims[1] = {2};
- vtAttr.arrayDimensions = arrayDims;
- vtAttr.arrayDimensionsSize = 1;
- vtAttr.displayName = UA_LOCALIZEDTEXT("en-US", "2DPoint Type");
- /* a matching default value is required */
- UA_Double zero[2] = {0.0, 0.0};
- UA_Variant_setArray(&vtAttr.value, zero, 2, &UA_TYPES[UA_TYPES_DOUBLE]);
- UA_Server_addVariableTypeNode(server, UA_NODEID_NULL,
- UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE),
- UA_NODEID_NUMERIC(0, UA_NS0ID_HASSUBTYPE),
- UA_QUALIFIEDNAME(1, "2DPoint Type"), UA_NODEID_NULL,
- vtAttr, NULL, &pointTypeId);
- }
- /**
- * Now the new variable type for *2DPoint* can be referenced during the creation
- * of a new variable. If no value is given, the default from the variable type
- * is copied during instantiation.
- */
- static UA_NodeId pointVariableId;
- static void
- addVariable(UA_Server *server) {
- /* Prepare the node attributes */
- UA_VariableAttributes vAttr = UA_VariableAttributes_default;
- vAttr.dataType = UA_TYPES[UA_TYPES_DOUBLE].typeId;
- vAttr.valueRank = UA_VALUERANK_ONE_DIMENSION;
- UA_UInt32 arrayDims[1] = {2};
- vAttr.arrayDimensions = arrayDims;
- vAttr.arrayDimensionsSize = 1;
- vAttr.displayName = UA_LOCALIZEDTEXT("en-US", "2DPoint Variable");
- vAttr.accessLevel = UA_ACCESSLEVELMASK_READ | UA_ACCESSLEVELMASK_WRITE;
- /* vAttr.value is left empty, the server instantiates with the default value */
- /* Add the node */
- UA_Server_addVariableNode(server, UA_NODEID_NULL,
- UA_NODEID_NUMERIC(0, UA_NS0ID_OBJECTSFOLDER),
- UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT),
- UA_QUALIFIEDNAME(1, "2DPoint Type"), pointTypeId,
- vAttr, NULL, &pointVariableId);
- }
- /**
- * The constraints of the variable type are enforced when creating new variable
- * instances of the type. In the following function, adding a variable of
- * *2DPoint* type with a string value fails because The value does not match the
- * variable type constraints. */
- static void
- addVariableFail(UA_Server *server) {
- /* Prepare the node attributes */
- UA_VariableAttributes vAttr = UA_VariableAttributes_default;
- vAttr.dataType = UA_TYPES[UA_TYPES_DOUBLE].typeId;
- vAttr.valueRank = UA_VALUERANK_SCALAR; /* a scalar. this is not allowed per the variable type */
- vAttr.displayName = UA_LOCALIZEDTEXT("en-US", "2DPoint Variable (fail)");
- UA_String s = UA_STRING("2dpoint?");
- UA_Variant_setScalar(&vAttr.value, &s, &UA_TYPES[UA_TYPES_STRING]);
- /* Add the node will return UA_STATUSCODE_BADTYPEMISMATCH*/
- UA_Server_addVariableNode(server, UA_NODEID_NULL,
- UA_NODEID_NUMERIC(0, UA_NS0ID_OBJECTSFOLDER),
- UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT),
- UA_QUALIFIEDNAME(1, "2DPoint Type (fail)"), pointTypeId,
- vAttr, NULL, NULL);
- }
- /**
- * The constraints of the variable type are enforced when writing the datatype,
- * valuerank and arraydimensions attributes of the variable. This, in turn,
- * constrains the value attribute of the variable. */
- static void
- writeVariable(UA_Server *server) {
- UA_StatusCode retval = UA_Server_writeValueRank(server, pointVariableId, UA_VALUERANK_ONE_OR_MORE_DIMENSIONS);
- UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_USERLAND,
- "Setting the Value Rank failed with Status Code %s",
- UA_StatusCode_name(retval));
- }
- /** It follows the main server code, making use of the above definitions. */
- static volatile UA_Boolean running = true;
- static void stopHandler(int sign) {
- UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "received ctrl-c");
- running = false;
- }
- int main(void) {
- signal(SIGINT, stopHandler);
- signal(SIGTERM, stopHandler);
- UA_Server *server = UA_Server_new();
- UA_ServerConfig_setDefault(UA_Server_getConfig(server));
- addVariableType2DPoint(server);
- addVariable(server);
- addVariableFail(server);
- writeVariable(server);
- UA_StatusCode retval = UA_Server_run(server, &running);
- UA_Server_delete(server);
- return retval == UA_STATUSCODE_GOOD ? EXIT_SUCCESS : EXIT_FAILURE;
- }
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