Returns TRUE if number/path/refnum is not a number (NaN),<Not a Path>, or not a refnum. Otherwise, this function returns FALSE.
Use this function to make sure a reference to an object, such as a VI, application, or control, still resides in system memory and was not closed.
The connector pane displays the default data types for this polymorphic function.

![]() | Note This function works only on references generated by LabVIEW functions. Do not use this function to determine the validity of a rendezvous refnum, semaphore refnum, or any refnum created by the GOOP wizard, LabVIEW Database Connectivity Toolkit, or LabVIEW Internet Toolkit. For rendezvous refnums, use the Not A Rendezvous VI. For semaphore refnums, use the Not A Semaphore VI. For all other GOOP refnums or toolkit refnums, use the VIs defined by the refnum creator. |