Function

isnull( value )

Returns true if value is null, false otherwise.

See also: a!defaultValue, length()

Parameters

Keyword	Type	Description
value	Any Type	Value to check for null.

Returns

Boolean

Usage considerations

Empty arrays and parameters

• Empty arrays return false when passed to the isnull() function.
• The function will not work without a parameter. It is typically used to test whether a Process Variable contains a null value.

Examples

isnull(!userPV) returns true where userPV is a process variable of type User, which is null.