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
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