Multiple-variable SET gives <UNIMPLEMENTED> with special variables

The error arises because using the multi-variable SET syntax like SET ($ZE,$EC)="" on special variables such as $ZE and $EC is not supported in InterSystems IRIS. These special variables have specific restrictions and cannot use certain syntaxes for assignment. Instead, you need to use the single-instruction form, e.g., SET $ZE="", $EC="" [1][2].

The multivariable SET syntax only works with standard variables but not special variables due to these restrictions [1][2].

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