problem with System()

AlvaroS · S SGaist 24 Jun 2016, 07:50

@SGaist Now I do this and nothing as well..

    QString program = "princi";
    QStringList arguments;

    arguments << "0" << QString::number(wps.front().x()) << QString::number(wps.front().y()) << "0" << QString::number(wps.back().x()) << QString::number(wps.back().y()) << "prueba_princi.bmp" << "0 0 +" ;

    QString folder = "/home/";

    QProcess *myProcess = new QProcess(this);

    myProcess->setWorkingDirectory(folder);

    myProcess->start(program,arguments);

SGaist · 24 Jun 2016, 08:01

What is the full path to princi ? And what is the full path to your application ?

AlvaroS · S SGaist 24 Jun 2016, 07:59

@SGaist Full path of princi (which is the executable) is /home/
and full path of my QT aplication is /home/workspace

jsulm · 24 Jun 2016, 08:23

/home is not the full path to your application except it is called home and is located in the root directory.
So, you can start the program in a shell with /home/princi?
Did you try it?
This is quite strange path: in /home you usually have a directory for each user and /home is not writable by normal user.

AlvaroS · J jsulm 24 Jun 2016, 08:09

@jsulm sorry yes, it is in /home/user1/ but it does not run as well...

mrjj · 24 Jun 2016, 08:28

@AlvaroS said:

QString program = "princi";

should be

QString program = "/home/user1/princi";

?

AlvaroS · 24 Jun 2016, 08:29

@mrjj It works in the same way... :(

jsulm · 24 Jun 2016, 08:31

@AlvaroS So, if you enter /home/user1/princi in a terminal window and press enter it does not start? What happens? Any error message?

mrjj · 24 Jun 2016, 08:38

@AlvaroS

Ok, you must debug then
try to use
http://doc.qt.io/qt-5/qprocess.html#error
to see what it thinks.

AlvaroS · 24 Jun 2016, 08:33

@jsulm In a terminal if I write

./princi 0 747.37 427.68 0 844.37 42.54 prueba_princi.bmp 0 0 +

in /home/user1/ directory it runs good

jsulm · wrote on 24 Jun 2016, 08:33

@AlvaroS Then try what @mrjj suggested

AlvaroS · 24 Jun 2016, 08:40

This post is deleted!

AlvaroS · wrote on 24 Jun 2016, 08:39

@AlvaroS said:

@jsulm In a terminal if I write
./princi 0 747.37 427.68 0 844.37 42.54 prueba_princi.bmp 0 0 +
in /home/user1/ directory it runs good

@jsulm said:

@AlvaroS Then try what @mrjj suggested

okey, it gives me UnknowError.... http://doc.qt.io/qt-5/qprocess.html#ProcessError-enum

mrjj · 24 Jun 2016, 08:42

@AlvaroS

well you can use
qDebug() "qproc: " << myProcess->error();

and check the code in
http://doc.qt.io/qt-5/qprocess.html#ProcessError-enum

AlvaroS · 24 Jun 2016, 08:43

@mrjj Yes thanks!! See my last post. Thanks again. It gives me Unknow error...

mrjj · 24 Jun 2016, 08:44

@AlvaroS

" This is the default return value of error()."

You do call it AFTER u call
myProcess->start(program,arguments); ?

AlvaroS · 24 Jun 2016, 08:46

@mrjj Yes:

    myProcess->start(program, arguments);

    QProcess::ProcessError error = myProcess->error();

mrjj · 24 Jun 2016, 08:48

@AlvaroS
hmm really odd then
it should say FailedToStart

Just to be 100% clear.

princi is never run ?

AlvaroS · M mrjj 24 Jun 2016, 08:46

@mrjj said:

@AlvaroS
hmm really odd then
it should say FailedToStart

Just to be 100% clear.

princi is never run ?

okey look.
if I write:

    myProcess->start(program, arguments);

    myProcess->waitForFinished(3000);

    QProcess::ProcessError error = myProcess->error();

Now error says:
QProcess::Crashed The process crashed some time after starting successfully.

mrjj · 24 Jun 2016, 08:54

so it sounds like your princi do run but it crashes?

oh. sorry my bad. start is async so calling error right after was
not correct.

waitForFinished fixed that.