automatic variables-_character_,numeric_,_error_

Yes all of them are automaticed variables(not user defined but system defined),you can also call them sas ‘keywords’.they are available in data step.
Letz see tis example—

Data new;
Set viks.cd;

Array myarray{*} $ _character_;/*this uses _character_ to refer all chracter variables in 'viks.cd',similar for _numeric_*/
/*sets missing values to string value’;*/
Do i=1 to dim(myarray);
If missing( myarray{i}) then
Myarray{i}='not specified';
End;
Drop I;
Run;

_error_--this automated variable is also available in data step.it can have one of the two possible values.1-for data error during execution of data step and 0 if there are no data errors.
Data errors—>placing character value in a numeric variable or vice-versa ,division by 0 or passing invalid arguments in the function.
NOTE->ALL THESE VARIABLES ARE ‘TEMPORARY ‘ AS THEY ARE NOT SAVED ALONG WITH THE DATA.