QProcess do not run an external application - c++

Question

I can run an external application using the following command:
system("/home/felippe/Área\\ de\\ Trabalho/Felippe/Mestrado/C_plus_plus/Codigos/build-Registration_ITK_CMAKE-Desktop_Qt_5_12_3_GCC_64bit-Default/Registration_ITK_CMAKE")
And the application runs successfully. But the system(.) command blocks the other commands until the application finishes. So I tried to implement this command in QT using the following code:
.h
#ifndef FOO_H
#define FOO_H
#include <QObject>
#include <iostream>
#include <QProcess>
class foo : public QObject
{
Q_OBJECT
public:
explicit foo(QObject *parent = nullptr);
signals:
public slots:
void process_started();
void processError(QProcess::ProcessError error);
private:
QProcess *process;
};
#endif // FOO_H
.cpp
#include "foo.h"
foo::foo(QObject *parent) : QObject(parent)
{
process = new QProcess();
bool status = QObject::connect( process, SIGNAL( started() ), this, SLOT( process_started() ) );
connect(process, &QProcess::errorOccurred, this, &foo::processError);
QString file = "/home/felippe/Área de Trabalho/Felippe/Mestrado/C_plus_plus/Codigos/build-Registration_ITK_CMAKE-Desktop_Qt_5_12_3_GCC_64bit-Default/Registration_ITK_CMAKE";
process->start(file);
std::cout << file.toStdString() << std::endl;
std::cout << "status: " << status << std::endl;
}
void foo::process_started()
{
std::cout << "It worked" << std::endl;
}
void foo::processError(QProcess::ProcessError error)
{
std::cout << "error enum val = " << error << std::endl;
}
main
#include <QCoreApplication>
#include <iostream>
#include "foo.h"
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
foo *f = new foo();
return a.exec();
}
When I run the process->start(file); I receive a error with value of 0, but when I run process->start(file, {"sudo"}); I receive a signal that the program run successfully, but anything is showed on the screen.
I'm trying to run on UBUNTU 16.04.
So, what is happening?

Answer 1

The most obvious difference is that system passes your string to the shell, while QProcess::start takes a command and argument list separately.
I bet you will get "file not found" if you hook to the errorOccurred signal.
Solution: remove the \\ from your string, as those are only needed if a shell is involved.