CVI function not a number%2C path or refnum

[AcentK]

What CVI function should I use for not a number, path or refnum? Also, function to check for an empty path or empty file.  Examples including would be greatly appreciated.

[RobertoBozzolo]

Not a number, not a path, not a refnum are LabVIEW concepts that do not apply to CVI.

Paths in CVI a simple strings, so "not a path" can be an empty string.

The Programmer's Toolbox give a NotANumber () function that you may want to use to initialize a (double) value as well as a IsNotANumber () function for tests.

There isn't a C equivalent to RefNums: C (and CVI, of course) can use handles which are usually integers or unsigned integers, but other datatypes can be found in several libraries: each of them must be initialized in its proper way.