%IsNull function

Function

If the first parameter Arg is valid (i.e. the value of attribute VLD of parameter Arg is TRUE), the function returns the parameter Arg. If the first parameter Arg is invalid, the function returns the second parameter Replacement.

Declaration

UNIVAL %IsNull(
   UNIVAL in Arg
   UNIVAL in Replacement
 )

Parameters

Arg	Compared value.
Replacement	Replacement value if Arg is invalid.

Example

 INT _i, _j, _k

 _i  := %IsNull ( Sec, Min)         ; returns value of Sec, as it is always valid
 
 _i  := %SetInvalid(_i)              ; invalidate the value
 _j  := 999 
 _k  := %IsNull ( _i, _j)           ; returns value 999, as the value of _i is invalid

Related topics

%SetInvalid