%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, 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

Related pages:

Implemented  functions
Function arguments - types

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