set verify;

create procedure SET_SYMBOL (
    in  :symbol VARCHAR (255)
        by descriptor,
    in  :value_string VARCHAR (255)
        by descriptor)
    language SQL;
    external
        name LIB$SET_SYMBOL
        location 'SYS$SHARE:LIBRTL.EXE'
        language GENERAL
        parameter style GENERAL
    comment is 'Create a DCL symbol from SQL';

declare :my_value varchar (20);
begin set :my_value = 'Sample'; end;
begin call SET_SYMBOL ('MY_VALUE', :my_value); end;

rollback;