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  2. RPG400-L
  3. June 2012

Re: Explanation of a datastructure as a parameter...


On 2012-06-15, at 4:56 PM, rpg400-l-request@xxxxxxxxxxxx wrote:

The datastructure DayDs is defined like the template t_DayDs. I don't
want the procedure GetDaysOfWeek to be able to change subfield1. If I had
passed all 7 parameters I would have specified the keyword const for the
first parameter.

How or can I do with a keyword when I pass a datastructure.

Using CONST won't ensure that the DS cannot be modified in and of itself. If the subprocedure did not use CONST in its PI then nothing will be protected.

The keyword you need if you need to be absolutely sure that it cannot be changed is VALUE. That will _always_ pass a copy of the data to the subproc. With CONST a copy is only made if the definitions are different, so you are reliant on the called routine being "well behaved".


Jon Paris

www.partner400.com
www.SystemiDeveloper.com





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