QProcess and cmd.exe not working when path with with accented characters

Vec44

Re : [Solved] Running cmd.exe in QProcess without showing Command Prompt window?

I tried to copy files from deep folder ( longpath > 259) using QFile::copy(source, dest) but it does not work: I got ’file not fond’.

NB in W10, longpath is enabled.

If I do the same in a Windows console with ’copy source dest /Y’ files are found and copied.

So I try using QProcess and cmd.exe as described by topic/29517.
That works for paths with non accented characters like ’Deplaces’, but doesn’t with accented characters like ’Déplacés’.

In lineEdit, If I type ’copy [source] folder1\ folder2......\Déplacés\OneFile /Y, In textEdit, instead of that I see copy [source] folder1\ folder2......\DÙplacÙs\ which could explain that file isn’t fond...

When using ’process->write(ptr)’ the text of the command is changed and I get the error.
How could I overcome this?

Christian Ehrlicher

@Vec44 said in QProcess and cmd.exe not working when path with with accented characters:

How could I overcome this?

First by providing a minimal, compilable example on what you're doing.

ChrisW67

@Vec44 said in QProcess and cmd.exe not working when path with with accented characters:

In lineEdit, If I type ’copy [source] folder1\ folder2......\Déplacés\OneFile /Y, In textEdit, instead of that I see copy [source] folder1\ folder2......\DÙplacÙs\ which could explain that file isn’t fond...

Failing to handle character encoding correctly would be my guess.

Vec44

Hereafter the code used:

<
//MainWindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QTextCodec>
#include <QtDebug>

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);

//Increase size of text on screen
QFont font(this->font());
font.setPointSizeF(9.5);//tout en bloc -> texte, status, boutons, comboBox
QApplication::setFont(font);

process = new QProcess(this);
connect(process, SIGNAL(readyReadStandardOutput()), this, SLOT(on_StdoutAvailable()) );
connect(ui->lineEdit, SIGNAL(returnPressed()),
        this, SLOT(on_lineEdit_returnPressed()));
process->start("cmd.exe");

}

MainWindow::~MainWindow()
{
delete ui;
}

void MainWindow::on_lineEdit_returnPressed()
{
if (process->isOpen())
{
QByteArray ba(ui->lineEdit->text().toUtf8() + '\n') ;
char *ptr = ba.data();
int numBytes = process->write(ptr);

    process->write(ptr);

    //Check
	while (*ptr) {
        qDebug()<< "[" << *ptr << "]";
        ++ptr;
    }

    ui->lineEdit->clear();
}

}
void MainWindow::on_StdoutAvailable()
{
QByteArray ba = process->readAllStandardOutput();
QTextCodec* codec = QTextCodec::codecForName("IBM-850");//decode accented characters on screen

QString chaineBrute = codec->toUnicode(ba);//QTextEdit use Unicode for QString
ui->plainTextEdit->appendPlainText(chaineBrute);//show ocnverted string

}

//Mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QProcess>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();

public slots:
void on_lineEdit_returnPressed();
void on_StdoutAvailable();

private:
Ui::MainWindow *ui;
QProcess *process;
};

#endif // MAINWINDOW_H

/Command.pro
#-------------------------------------------------

Project created by QtCreator 2023-04-08T09:58:35

#-------------------------------------------------

QT += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = Command
TEMPLATE = app

SOURCES += main.cpp
mainwindow.cpp

HEADERS += mainwindow.h

FORMS += mainwindow.ui

/>

Vec44

@ChrisW67
Yes, I think so but unfortunately, all codecs I use fail (may be the way I code...).

Any idea about the way of coding text entered in LineEdit to be conform with one expected by cmd copy?

ChrisW67

@Vec44 Could you please edit your post and place the code in a code block (or blocks). That is the </> button above, or use three backticks ``` on a line before and after the code.

You are sending input to the running cmd.exe encoded as UTF-8 but reading the output from cmd.exe as CP-850. Try QString::toLocal8Bit() instead of QString::toUtf8(), or explicitly convert to CP-850. If your Windows has been configured to use UTF-8 rather than an 8-bit code page then you would adjust the reading conversion.

You should also look at QFile for information about encoding/decoding paths. You might try this with the static QFile::copy().

Vec44

@ChrisW67 Of course, I first try with < QFile:copy(source,dest) /> but it works <ith accented characters when short paths, when longpaths very time I got 'File not found'; it's the reason I think of use cmd.exe and copy as I tried whith success from windows terminal...

If I could overcome with codec it would be OK.

NB: In fact, instead of using lineEdit, I plane to pick source path from a text file (list of all the files I can't access for QFile:copy()).

Vec44

@ChrisW67 With QFile:copy() I'm unable to access deeppath as I mentioned previously and that is the reason why I use cmd.exe.

So I returned to my own code and changed the text picked up using lineEdit :
< void MainWindow::on_lineEdit_returnPressed()
{
if (process->isOpen())
{
QString s = ui->lineEdit->text() + "\n";
QTextCodec* codec = QTextCodec::codecForName("IBM-850");
QByteArray ba = codec->fromUnicode(s);
}
/>

And now all is working correctly!
'I tried first with dir ["longpath with accented characters"] and it works...