I don’t seem to have FreeThenNil I’m using FPC 3.0.4RC1 I don’t use Lazarus..
maybe it’s a Lazarus thing… or maybe it’s in a different unit
plotdraw.pax.pas(20,7) Error: Identifier not found "FreeThenNil"
James
From: fpc-pascal <fpc-pascal-boun...@lists.freepascal.org> On Behalf Of
Giuliano Colla
Sent: Monday, May 20, 2019 6:01 PM
To: fpc-pascal@lists.freepascal.org
Subject: Re: [fpc-pascal] Checking if a TStringList already exists
Il 20/05/2019 15:23, James Richters ha scritto:
Thank you very much for the explanation and examples of this! I am glad you
pointed out the FreeAndNill() function, I will defiantly be needing that.
James
Then you might also appreciate the function Assigned. Assigned(P) returns true
if P is non-nil, and false if P is Nil. Nothing fancy, just making the code
more readable.
>From fpc documentation:
Program Example96;
{ Program to demonstrate the Assigned function. }
Var P : Pointer;
begin
If Not Assigned(P) then
Writeln ('Pointer is initially NIL');
P:=@P;
If Not Assigned(P) then
Writeln('Internal inconsistency')
else
Writeln('All is well in FPC')
end.
Giuliano
P.S. In some rare case when dealing with complex objects you might need
FreeThenNil() in place of FreeAndNil(). Give a look to
https://lists.lazarus-ide.org/pipermail/lazarus/2011-April/062743.html
--
Do not do to others as you would have them do to you.They might have different
tastes.
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