open62541 ========= open62541 (http://open62541.org) is an open source and free implementation of OPC UA (OPC Unified Architecture). open62541 is a C-based library that contains all the necessary tools to set up a dedicated OPC UA server, to integrate OPC UA-based communication into existing applications (linking with C++ projects [is possible](examples/server.cpp)), or to create an OPC UA client. The library is distributed as a single pair of [header](http://open62541.org/open62541.h) and [source](http://open62541.org/open62541.c) files, that can be easily dropped into your project. An example server and client implementation can be found in the [/examples](examples/) directory or further down on this page. open62541 is licensed under the LGPL + static linking exception. That means **open62541 can be freely used also in commercial projects**, although changes to the open62541 library itself need to be released under the same license. The server and client implementations in the [/examples](examples/) directory are in the public domain (CC0 license). They can be used under any license and changes don't have to be published. [![Ohloh Project Status](https://www.ohloh.net/p/open62541/widgets/project_thin_badge.gif)](https://www.ohloh.net/p/open62541) [![Build Status](https://travis-ci.org/acplt/open62541.png?branch=master)](https://travis-ci.org/acplt/open62541) [![Coverage Status](https://coveralls.io/repos/acplt/open62541/badge.png?branch=master)](https://coveralls.io/r/acplt/open62541?branch=master) [![Coverity Scan Build Status](https://scan.coverity.com/projects/1864/badge.svg)](https://scan.coverity.com/projects/1864) ### Documentation A general introduction to OPC UA and the open62541 documentation can be found at http://open62541.org/doc. Build instruction are here: https://github.com/acplt/open62541/wiki/Building-open62541. For discussion and help, you can use - the [mailing list](https://groups.google.com/d/forum/open62541) - our [IRC channel](http://webchat.freenode.net/?channels=%23open62541) - the [bugtracker](https://github.com/acplt/open62541/issues) ### Contribute to open62541 As an open source project, we invite new contributors to help improving open62541. If you are a developer, your bugfixes and new features are very welcome. Note that there are ways to contribute even without deep knowledge of the project or the UA standard: - [Report bugs](https://github.com/acplt/open62541/issues) - Improve the [documentation](http://open62541.org/doc) - Work on issues marked as "[easy hacks](https://github.com/acplt/open62541/labels/easy%20hack)" ### Example Server Implementation Compile the examples with the single file distribution `open62541.h` and `open62541.c` from the latest [release](https://github.com/acplt/open62541/releases). With the GCC compiler, just run ```gcc -std=c99 open62541.c -o server```. ```c #include #include "open62541.h" #define WORKER_THREADS 2 /* if multithreading is enabled */ #define PORT 16664 UA_Boolean running = UA_TRUE; void signalHandler(int sign) { running = UA_FALSE; } int main(int argc, char** argv) { /* catch ctrl-c */ signal(SIGINT, signalHandler); /* init the server */ UA_Server *server = UA_Server_new(); UA_Server_addNetworkLayer(server, ServerNetworkLayerTCP_new(UA_ConnectionConfig_standard, PORT)); UA_Server_setLogger(server, Logger_Stdout_new()); /* add a variable node */ UA_Variant *myIntegerVariant = UA_Variant_new(); UA_Int32 myInteger = 42; UA_Variant_setScalarCopy(myIntegerVariant, &myInteger, &UA_TYPES[UA_TYPES_INT32]); UA_QualifiedName myIntegerName = UA_QUALIFIEDNAME(1, "the answer"); UA_NodeId myIntegerNodeId = UA_NODEID_STRING(1, "the.answer"); UA_NodeId parentNodeId = UA_NODEID_NUMERIC(0, UA_NS0ID_OBJECTSFOLDER); UA_NodeId parentReferenceNodeId = UA_NODEID_NUMERIC(0, UA_NS0ID_ORGANIZES); UA_Server_addVariableNode(server, myIntegerVariant, myIntegerName, myIntegerNodeId, parentNodeId, parentReferenceNodeId); /* run the server loop */ UA_StatusCode retval = UA_Server_run(server, WORKER_THREADS, &running); UA_Server_delete(server); return retval; } ``` ### Example Client Implementation ```c #include #include "open62541.h" int main(int argc, char *argv[]) { UA_Client *client = UA_Client_new(); UA_ClientNetworkLayer nl = ClientNetworkLayerTCP_new(UA_ConnectionConfig_standard); UA_StatusCode retval = UA_Client_connect(client, UA_ConnectionConfig_standard, nl, "opc.tcp://localhost:16664"); if(retval != UA_STATUSCODE_GOOD) { UA_Client_delete(client); return retval; } UA_ReadRequest req; UA_ReadRequest_init(&req); req.nodesToRead = UA_ReadValueId_new(); req.nodesToReadSize = 1; req.nodesToRead[0].nodeId = UA_NODEID_STRING(1, "the.answer"); req.nodesToRead[0].attributeId = UA_ATTRIBUTEID_VALUE; UA_ReadResponse resp = UA_Client_read(client, &req); if(resp.responseHeader.serviceResult == UA_STATUSCODE_GOOD && resp.resultsSize > 0 && resp.results[0].hasValue && resp.results[0].value.data /* an empty array returns a null-ptr */ && resp.results[0].value.type == &UA_TYPES[UA_TYPES_INT32]) printf("the answer is: %i\n", *(UA_Int32*)resp.results[0].value.data); UA_ReadRequest_deleteMembers(&req); UA_ReadResponse_deleteMembers(&resp); UA_Client_disconnect(client); UA_Client_delete(client); return UA_STATUSCODE_GOOD; } ```