examples/server_example_basic_io

There is an access error while using iec61850_client_example1 with server_example_basic_io.

From [1]:
    /* write a variable to the server */
    value = MmsValue_newVisibleString("libiec61850.com");
    IedConnection_writeObject(con, &error, "simpleIOGenericIO/GGIO1.NamPlt.vendor", IEC61850_FC_DC, value);

The error code is IED_ERROR_ACCESS_DENIED = 21.

By default access to variables with FC=DC and FC=CF is not allowed, fix this
by changing the access policy as suggested by [2].

[1] https://github.com/mz-automation/libiec61850/blob/v1.4.2.1/examples/iec61850_client_example1/client_example1.c#L71
[2] https://libiec61850.com/libiec61850/documentation/iec-61850-client-tutorial/#comment-61994

Signed-off-by: Romain Naour <romain.naour@smile.fr>

examples/server_example_basic_io/server_example_basic_io.c

@@ -136,6 +136,12 @@ main(int argc, char** argv)
 
     IedServer_setConnectionIndicationHandler(iedServer, (IedConnectionIndicationHandler) connectionHandler, NULL);
 
+    /* By default access to variables with FC=DC and FC=CF is not allowed.
+     * This allow to write to simpleIOGenericIO/GGIO1.NamPlt.vendor variable used
+     * by iec61850_client_example1.
+     */
+    IedServer_setWriteAccessPolicy(iedServer, IEC61850_FC_DC, ACCESS_POLICY_ALLOW);
+
     /* MMS server will be instructed to start listening for client connections. */
     IedServer_start(iedServer, 102);