Rgui.exe 4.2.0 does not receive characters via the Windows API's PostMessage function

On 5/6/22 07:03, jcfaria wrote:

Dear Duncan,
I believe the problem is of a different nature.
I get TRUE 3 times running the code below:

procedure TfMain.btnPasteClick(Sender: TObject);
var
  i: integer;
  sTmp: string;
  hBN: HWND;
  j: bool;

begin
  hBN:= FindWindowA(nil,
                    'R Console (64-bit)');

  sTmp:= 'sd';

  for i:= 1 to Length(sTmp) do begin
    j:= PostMessage(hBN,
                    WM_CHAR,
                    Ord(sTmp[i]),
                    0);

    ShowMessage(BoolToStr(j,
                          True));
  end;

  j:= PostMessage(hBN,
              WM_KEYDOWN,
              VK_RETURN, 0);

  ShowMessage(BoolToStr(j,
                        True));
end;

That is, Rgui is receiving the message of the characters (via PostMessage), but it is blocking because it does not show them in the console.
The only thing Rgui blames is Carriage Return, as it adds an additional prompt with each run.

I can't provide a good guess what impacted your use, but if you could give me a full example, ideally in C, which can be compiled with Rtools42 (so gcc, MinGW) and I can edit/recompile, and works with R 4.1, I am happy to help debugging on 4.2.

Rgui now uses GraphApp Unicode windows on systems where it didn't before, because it uses UTF-8 also on systems it didn't before (on systems that would use a single-byte locale in R 4.1). These Unicode windows are a different code path and there may be bugs not reported previously, including processing inputs (recently I fixed handling of accents, for example). Otherwise indeed R now uses UTF-8 as native encoding and UCRT as the C runtime.

Best
Tomas

Best,
///\\\///\\\///\\\///\\\///\\\///\\\///\\\///\\\///\\\///\\\
Jose Claudio Faria
UESC/DCET/Brasil
joseclaudio.faria at gmail.com
Telefones:
55(73)3680.5545 - UESC
55(73)99966.9100 - VIVO
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If you have software to deal with statistics, you have arms,
if you have good software, you have arms and legs,
if you have software like R, you have arms, legs and wings...
the height of your flight depends only on you.

------ Mensagem original ------
De: "Duncan Murdoch" <murdoch.duncan at gmail.com>
Para: "jcfaria" <joseclaudio.faria at gmail.com>; r-devel at r-project.org
Enviado(s): 05/05/2022 13:17:53
Assunto: Re: [Rd] Rgui.exe 4.2.0 does not receive characters via the Windows API's PostMessage function

On 05/05/2022 11:17 a.m., jcfaria wrote:

Hello,

Rgui.exe 4.2.0 does not receive characters via the Windows API's
PostMessage function.

The Tinn-R project sends messages to Rgui.exe (SDI mode) via the Windows
API's PostMessage function.
A simplification of the code (in object Pascal) can be seen below.

procedure TfMain.btnPasteClick(Sender: TObject);
var
    i: integer;
    sTmp: WideString;
    hBN: HWND;

begin
    hBN:= FindWindowA(nil,
                      'R Console (64-bit)');

    sTmp:= 'sd';

    for i:= 1 to Length(sTmp) do begin
      PostMessage(hBN,
                  WM_CHAR,
                  Ord(sTmp[i]),
                  0);
    end;

    PostMessage(hBN,
                WM_KEYDOWN,
                VK_RETURN, 0);
end;

This code has always worked fine for all versions of Rgui.exe with the
exception of the last one released, ie 4.2.0.

We've been trying to get around the problem on the Object Pascal side,
but without success so far.

Does anyone connected to the compilation of Rqui.exe know what the
problem is?

It could be that the new build enforces Windows security more stringently.  More details are described in the answer to this question:  https://stackoverflow.com/a/40139498/2554330, but at a minimum you should be checking the return value from PostMessage.

Duncan Murdoch

Best,
///\\\///\\\///\\\///\\\///\\\///\\\///\\\///\\\///\\\///\\\
Jose Claudio Faria
UESC/DCET/Brasil
joseclaudio.faria at gmail.com
Telefones:
55(73)3680.5545 - UESC
55(73)99966.9100 - VIVO
///\\\///\\\///\\\///\\\///\\\///\\\///\\\///\\\///\\\///\\\
If you have software to deal with statistics, you have arms,
if you have good software, you have arms and legs,
if you have software like R, you have arms, legs and wings...
the height of your flight depends only on you.

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