On 2020-09-12 23:03, Tomas Hajny wrote:
On 2020-09-12 18:51, Jonas Maebe via fpc-pascal wrote:
On 12/09/2020 18:44, Sven Barth via fpc-pascal wrote:
Jonas Maebe via fpc-pascal <fpc-pascal@lists.freepascal.org
<mailto:fpc-pascal@lists.freepascal.org>> schrieb am Sa., 12. Sep.
2020,
17:47:
.
.
While performing some tests, I came across other things which are not
very nice either (those are specific to the Win32/Win64 target due to
the difference between process codepage and console codepage). Let's
take the following test program:
{$codepage cp1250}
{$IFDEF USECRT}
uses
Crt;
{$ENDIF USECRT}
const
S = 'žluťoučký kůň';
var
T: string;
begin
T := S;
{$IFDEF USECRT}
Write ('Using Crt');
{$ELSE USECRT}
Write ('Not using Crt');
{$ENDIF USECRT}
WriteLn (S);
WriteLn (T);
WriteLn (DefaultSystemCodepage);
WriteLn (TextRec (Output).Codepage);
end.
Let's compile it _without_ -dUSECRT and _with_ -Mfpc first. The
original poster uses the same default codepage as me. If I start
cmd.exe and run "chcp" without parameters, it shows codepage 852 as
the console codepage. Now run the test program. It shows that the
codepage for the default file handle Output matches the console
codepage (as it should), but the string output is incorrect for both
WriteLn(S) and WriteLn(T) lines. If you perform "chcp 1250" and run
the program again, the codepages match and the string output is
correct.
If you compile the same program with -dUSECRT, the output is correct
for both WriteLn calls regardless from the console codepage setting
(i.e. both for "chcp 852" and for "chcp 1250" - and also for "chcp
65001").
If you compile the same program with -dUSECRT and -Mdelphi together
and run the program in a console window set to codepage 852 (i.e. the
default setting here), the first WriteLn call is wrong, whereas the
second gives a correct result (due to the fact that T becomes an
ansistring in mode Delphi and dynamic translation is thus performed as
opposed to the case when a shortstring or an untyped constant are
passed).
Questions resulting from my test above and the observed inconsistencies:
1) Wouldn't it be better if shortstrings are treated the same way as
ansistrings with CP_ACP? This would make a difference only during
assignments to strings with different codepages. Since strings with
different codepages didn't exist in the past (and in the current
situation they are simply broken), this change shouldn't break
compatibility hopefully.
2) Shouldn't WriteLn with a untyped string constant parameter result in
calling some Unicode based version of WriteLn rather than the
shortstring overloaded version (since the constant is stored in UTF-16
internally)?
3) Shouldn't we try to make the output of Write with and without unit
Crt compatible to each other? If we do so, what should be the encoding
used for output redirected to a file - should it use
DefaultSystemCodePage, or scpConsoleCP, or what (remember that this
question doesn't exist with unit Crt, because unit Crt isn't compatible
with redirection).
Tomas
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