Hi @epfeuffer,

Suggest you print the value, before casting it into double. If it's not a double, for example, if it's a blank, you can not cast double out of it.

Guessing here, but I think what is stopping you is blanks.

Please see this previous discussion

Let us know if this helps?

Hello @epfeuffer,

EMA API is thread-safe. Please see EMA C++ API Concepts Guide -> API Features section.

Yes, one can add and remove subscriptions while subscribing to data.

In terms of the best practices while achieving very high performance with EMA C++, it may be helpful to review Perf Consumer threaded example. It can be found in Elektron C++ SDK, in EMA\Examples\PerfTools\EmaCppConsPerf.

Thank you for the fast reply. the call to reg hangs and never comes back. how should i interpret that?

Hello @epfeuffer,

I would start with a question, in order to understand exactly what you observe.

Have you tested with our standard examples and tutorials for EMA C++, do they run for you?

Quickstart guide, select for your infra connectivity

EMA C++ Consumer Tutorials

Is the issue limited to the newly written custom consumer?

Hi i'm connected and receiving data, able to subscribe while receiving data, which is good, but i've determined the sticking point. using the function fe.getReal().getAsDouble() causes the code to halt, if i exclude this function, all works fine. Is this function using a static buffer or something that's not re-entrant?

ok, i'll try that.. is there a class reference ? does the code throw and exception or just hang?

Here is the link to EMA Reference Guide , click where is says "Click Here To Launch".

You should be able to, if this is what is happening, check for blanks prior as in the discussion above, or catch the Exception. Usually, the first approach is preferred.