When using smRead(), and invalid parameter is being read as a 0. Is there a way to determine in a script if a parameter is invalid? Unfortunately, I cannot use 0 as the indicator, because 0 could also be valid data.

I actually just ran into this same situation, except I also want to SET parameters as invalid. This stems from a desire to use the invalid state as a way to control which gauges are seen on the screen.

smRead() returns the validity of the parameter.

i.e.
dataValid = smRead(dataHandle, dataVariable);

Thanks. I missed that first line in the scripting guide that explained it.