The COLUMNS= suboption places DATA step variables into columns that are defined in the table definition. For instance, the first column-specification specifies that the first column of the output object contains the values of the variable COUNTRY and that it uses the column definition named char_var. GENERIC= must be set to ON in both the table definition and each column assignment in order for multiple variables to use the same column definition. The FORMAT= suboption specifies a format for the column. The DYNAMIC= suboption provides the value of the dynamic variable COLHD for the current column. Notice that for the first column the column header is Country, and for the second column, which uses the same column definition, the column header is Year. 
        columns=(
           char_var=country(generic=on format=$cntry.
                    dynamic=(colhd='Country'))
           char_var=type(generic dynamic=(colhd='Year'))
           num_var=kilotons(generic=on format=comma12.
                   dynamic=(colhd='Kilotons'))
           )
        );