[fpc-devel] TEncoding.Default and default encoding for TStrings.LoadFrom*()
lazarus at kluug.net
Fri Dec 27 01:52:21 CET 2019
On 27.12.2019 0:19, Michael Van Canneyt wrote:
> On Thu, 26 Dec 2019, Ondrej Pokorny wrote:
>> On 26.12.2019 19:29, Michael Van Canneyt wrote:
>>> So no, I don't think these need to be changed/merged. What IMO can
>>> be discussed is
>>> which of these 2 need to be used as the default codepage in other
>>> code. It
>>> should then resolve the problems that appear, I think.
>> That would be possible as well. But still please reconsider it:
>> One reason: just from the convention - the default codepage to use
>> should be TEncoding.Default. That is intuitive.
>> Second reason: Now we have TEncoding.ANSI = TEncoding.Default. 2
>> equal properties. And another FPC-only property
>> TEncoding.SystemEncoding. That means 3 properties for 2 values.
> As far as I know, TEncoding.ANSI = CP_ACP.
This is indeed not correct. See
CP_ACP: this value represents the currently set "default system code
page". See #Code page settings for more information.
The code for it is in sysos.inc:
function TranslatePlaceholderCP(cp: TSystemCodePage): TSystemCodePage;
case cp of
Whereas TEncoding.ANSI is the WIN-ANSI OS encoding:
class function TEncoding.GetANSI: TEncoding;
TStandardCodePageEnum = (
scpAnsi, // system Ansi code page (GetACP on windows)
- as you can see the CP_ACP value does not correspond with the GetACP
WinAPI call result. (But this is wanted as documented in
> Why should this equal TEncoding.Default ?
class function TEncoding.GetDefault: TEncoding;
Result := GetANSI;
> I think TEncoding.Default = CP_UTF8 on linux ?
Yes, in FPC this is correct. Also TEncoding.ANSI =CP_UTF8 on linux in FPC.
> The main problem I see is that there is the system (OS) encoding, and the
> encoding specified by DefaultSystemCodePage.
> These do not necessarily agree. So it makes sense to have 2
> TEncodings: one
> for the system encoding, one for the DefaultSystemCodePage variable. They
> will not be equal.
> If they were, then the DefaultSystemCodePage variable makes no sense
Yes, indeed. Therefore I suggested
* TEncoding.Default for the DefaultSystemCodePage variable
* TEncoding.ANSI for the system encoding.
Currently we have
* TEncoding.SystemEncoding for the DefaultSystemCodePage variable
* both TEncoding.ANSI and TEncoding.Default for the system encoding.
(TEncoding.ANSI and TEncoding.Default are equal in FPC.)
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