open62541/examples/client.c

#include <stdio.h>

#include "ua_types.h"
#include "ua_server.h"
#include "logger_stdout.h"
#include "networklayer_tcp.h"

int main(void) {
  UA_Client *client = UA_Client_new(UA_ClientConfig_standard, Logger_Stdout_new());
  UA_StatusCode retval = UA_Client_connect(client, ClientNetworkLayerTCP_connect, "opc.tcp://localhost:16664");
  if(retval != UA_STATUSCODE_GOOD) {
    UA_Client_delete(client);
    return retval;
  }

  UA_DateTime raw_date = 0;
  UA_String* string_date = UA_String_new();
  // Read node's value
  UA_ReadRequest rReq;
  UA_ReadRequest_init(&rReq);
  rReq.nodesToRead = UA_Array_new(&UA_TYPES[UA_TYPES_READVALUEID], 1);
  rReq.nodesToReadSize = 1;
  rReq.nodesToRead[0].nodeId = UA_NODEID_NUMERIC(0, 2258);
  rReq.nodesToRead[0].attributeId = UA_ATTRIBUTEID_VALUE;

  UA_ReadResponse rResp = UA_Client_read(client, &rReq);
  if(rResp.responseHeader.serviceResult == UA_STATUSCODE_GOOD &&
     rResp.resultsSize > 0 && rResp.results[0].hasValue &&
     UA_Variant_isScalar(&rResp.results[0].value) &&
     rResp.results[0].value.type == &UA_TYPES[UA_TYPES_DATETIME]) {
      raw_date = *(UA_DateTime*)rResp.results[0].value.data;
      printf("raw date is: %llu\n", raw_date);
      UA_DateTime_toString(raw_date, string_date);
      printf("string date is: %.*s\n", string_date->length, string_date->data);
  }

  UA_ReadRequest_deleteMembers(&rReq);
  UA_ReadResponse_deleteMembers(&rResp);
  UA_String_delete(string_date);

  UA_Client_disconnect(client);
  UA_Client_delete(client);
  return 0;
}