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pcall (protected call)

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Created13.11.2019 07:44

Geni Meier (Gemini0915) 13.11.2019 07:44
Hi there,

I want to build a tractor cockpit with displays, gauges and indicators. As i know the lua interpreter is running in a 'sandbox mode', so some lua functions are not available. My inelegant solution would be writing data (e.g. speed, rpm, torque, etc) into a data file on a RAM-disk, read the data with an external script (Python) and send it to the cockpit hardware via a serial interface.

Of course there will occur an error if the file is already open by a script and the other tries to open it. I found in the lua reference the error handler function pcall, but all trials to get this function to work failed (without any error message).

Long story, short question : Is the pcall function available for lua scripts in the GIANTS engine ?

Bilbo Beutlin (BBeutlin) 13.11.2019 10:46
Quite simple: if you can't use it, it isn't implemented.

In practice that is no problem. You should launch the write procedure via a timer, let's say 2-5x per second. That's way enough for an external program to read the datas.
For safety you may enclose the read/write procedures in a loop "repeat ... until (no_error)".

Geni Meier (Gemini0915) 13.11.2019 13:28
Got it ! ... Many thanks for your reply and the hint :)

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