The variant class includes some helpful conversion operators. In the SDK (1.5.0), see include/comm.datalayer/comm/datalayer/variant.h. I was able to read PLC variable Position (defined as REAL), using the following: result = client->readSync(temp, &value); float f = float(value); (In your case, with Position defined as LREAL, you'll need to use double, but the principle should be the same...)
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