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https://github.com/open62541/open62541.git
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97 lines
3.7 KiB
C
97 lines
3.7 KiB
C
/* This work is licensed under a Creative Commons CCZero 1.0 Universal License.
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* See http://creativecommons.org/publicdomain/zero/1.0/ for more information. */
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/* Enable POSIX features */
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#if !defined(_XOPEN_SOURCE) && !defined(_WRS_KERNEL)
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# define _XOPEN_SOURCE 600
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#endif
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#ifndef _DEFAULT_SOURCE
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# define _DEFAULT_SOURCE
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#endif
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/* On older systems we need to define _BSD_SOURCE.
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* _DEFAULT_SOURCE is an alias for that. */
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#ifndef _BSD_SOURCE
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# define _BSD_SOURCE
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#endif
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/**
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* Client disconnect handling
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* --------------------------
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* This example shows you how to handle a client disconnect, e.g., if the server
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* is shut down while the client is connected. You just need to call connect
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* again and the client will automatically reconnect.
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*
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* This example is very similar to the tutorial_client_firststeps.c. */
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#include "open62541.h"
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#include <signal.h>
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#ifdef _WIN32
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# include <windows.h>
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# define UA_sleep_ms(X) Sleep(X)
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#else
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# include <unistd.h>
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# define UA_sleep_ms(X) usleep(X * 1000)
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#endif
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UA_Boolean running = true;
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UA_Logger logger = UA_Log_Stdout;
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static void stopHandler(int sign) {
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UA_LOG_INFO(logger, UA_LOGCATEGORY_CLIENT, "Received Ctrl-C");
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running = 0;
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}
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int main(void) {
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signal(SIGINT, stopHandler); /* catches ctrl-c */
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UA_ClientConfig config = UA_ClientConfig_default;
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/* default timeout is 5 seconds. Set it to 1 second here for demo */
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config.timeout = 1000;
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UA_Client *client = UA_Client_new(config);
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/* Read the value attribute of the node. UA_Client_readValueAttribute is a
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* wrapper for the raw read service available as UA_Client_Service_read. */
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UA_Variant value; /* Variants can hold scalar values and arrays of any type */
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UA_Variant_init(&value);
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/* Endless loop reading the server time */
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while (running) {
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/* if already connected, this will return GOOD and do nothing */
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/* if the connection is closed/errored, the connection will be reset and then reconnected */
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/* Alternatively you can also use UA_Client_getState to get the current state */
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UA_StatusCode retval = UA_Client_connect(client, "opc.tcp://localhost:4840");
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if (retval != UA_STATUSCODE_GOOD) {
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UA_LOG_ERROR(logger, UA_LOGCATEGORY_CLIENT, "Not connected. Retrying to connect in 1 second");
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/* The connect may timeout after 1 second (see above) or it may fail immediately on network errors */
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/* E.g. name resolution errors or unreachable network. Thus there should be a small sleep here */
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UA_sleep_ms(1000);
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continue;
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}
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/* NodeId of the variable holding the current time */
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const UA_NodeId nodeId =
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UA_NODEID_NUMERIC(0, UA_NS0ID_SERVER_SERVERSTATUS_CURRENTTIME);
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retval = UA_Client_readValueAttribute(client, nodeId, &value);
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if (retval == UA_STATUSCODE_BADCONNECTIONCLOSED) {
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UA_LOG_ERROR(logger, UA_LOGCATEGORY_CLIENT, "Connection was closed. Reconnecting ...");
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continue;
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}
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if (retval == UA_STATUSCODE_GOOD &&
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UA_Variant_hasScalarType(&value, &UA_TYPES[UA_TYPES_DATETIME])) {
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UA_DateTime raw_date = *(UA_DateTime *) value.data;
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UA_DateTimeStruct dts = UA_DateTime_toStruct(raw_date);
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UA_LOG_INFO(logger, UA_LOGCATEGORY_USERLAND, "date is: %02u-%02u-%04u %02u:%02u:%02u.%03u",
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dts.day, dts.month, dts.year, dts.hour, dts.min, dts.sec, dts.milliSec);
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}
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UA_Variant_deleteMembers(&value);
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UA_sleep_ms(1000);
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};
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/* Clean up */
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UA_Variant_deleteMembers(&value);
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UA_Client_delete(client); /* Disconnects the client internally */
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return UA_STATUSCODE_GOOD;
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}
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