Well, your result isn't local, in the sense that the function itself is not local -- the return value has the same scope as the function. Memory for a record is allocated when the record is declared, says delphi help. A question you might ask is "when is memory for a record freed?".
If it were me, I would use a tobject instead of a record, and I would use it
this way:
function MdbU.GetCurrCustomer(oCustRec: TMyCustRec): boolean;
begin
oCustRec.lname := CustRec.Fields['l_name'].Value;
oCustRec.fname := CustRec.Fields['f_name'].Value;
end;
The calling routine would do something like this:
oCustRec := TMyCustRec.Create;
if (dbu.GetCurrCustomer(oCustRec) then begin
.. do stuff with the name ..
end
else begin
.. deal with the error ..
end;
...
oCustRec.Free;
Jeremy
-----Original Message-----
From: advanced_delphi@yahoogroups.com on behalf of nf4lham
Sent: Sun 6/1/2008 11:07 AM
To: advanced_delphi@yahoogroups.com
Subject: [advanced_delphi] Re: Persistant values shouldn't be
Thanks Jeremy -
True, but isn't result local to the routine? I thought it was
destroyed when the method exited and was reinstanced when the method
was entered.
I made a small app with just those 2 units and result didn't persist,
so I'm confused.
Aside from
result.lname := '';
how would I clear it?
--- In advanced_delphi@yahoogroups.com, "Jeremy Grand" <[EMAIL PROTECTED]>
wrote:
>
> You're creating your object in the initialization area; I don't see
where it is cleared.
>
> jhg
>
>
>
> -----Original Message-----
> From: advanced_delphi@yahoogroups.com on behalf of nf4lham
> Sent: Sat 5/31/2008 7:45 PM
> To: advanced_delphi@yahoogroups.com
> Subject: [advanced_delphi] Persistant values shouldn't be
>
> I call a method in another unit (dbUnit) to retrieve a record from a
> database.
>
> On a successful query another method in dbUnit fills a record type to
> be passed back to the calling unit. dbUnit looks like this
> unit dbUnit;
>
> interface
> uses
> SysUtils, Classes, Windows, Variants, DAO_TLB, dialogs, comObj;
>
> type
> TMyCustRec = packed record
> fname: string;
> lname: string;
> end;
>
> type
> TMyDBU = class(TObject)
> private
> public
> function GetCurrCustomer: TMyCustRec;
> end;
> var
> DBU: TMYDBU;
>
> implementation
>
> function MdbU.GetCurrCustomer: TMyCustRec;
> begin
> result.lname := CustRec.Fields['l_name'].Value;
> result.fname := CustRec.Fields['f_name'].Value;
> end;
>
> initialization
> DBU := TMYDBU.Create;
> end.
>
> The call from the main unit is like:
>
> procedure GetaCustomer;
> var
> retrec: TMyCustRec;
> begin
> retrec := DBUnit.DBU.GetCurrCustomer;
> end;
>
> On subsequent calls, result.lname & result.fname are still populated
> with values from the previous call.They're acting like global
> variables. Why?
>
> Thanks,
> Mike
>
<<winmail.dat>>
