[fpc-pascal] reference-counted function results not initialized to nil
pascaldragon at googlemail.com
Sun Jun 26 14:13:42 CEST 2016
Am 26.06.2016 12:10 schrieb "Jürgen Hestermann" <juergen.hestermann at gmx.de>:
> Am 2016-06-26 um 01:19 schrieb Karoly Balogh (Charlie/SGR):
> > No. Local variables are not initialized by default. Managed type or not,
> > doesn't make a difference.
> This is not true.
> Local variables of managed types are of course initialized!
> If you declare
> var S : String;
> then it is of course initialized to nil.
> Otherwise the (random) pointer stored in S would be used
> to change the reference counter when you assign:
> S := '';
> The only exception (at least since FPC 3) is the function result
> which is totally unexpected.
> Why such an exception?
> And it is not even documented (at least not within FPC)!
> Which I find a bit strange because it is very important to know.
> Omitting such information in the documentation is not good.
> it says:
> "When declaring a variable of a dynamic array type, the initial length of
the array is zero."
> but no word about that this is not true when this array is a the result
of a function.
But also no word that it is true either, cause you're not declaring a
variable for the Result.
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