problem with System()

AlvaroS

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

jsulm

/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

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

mrjj

@AlvaroS said:

QString program = "princi";

should be

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

?

AlvaroS

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

jsulm

@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

@AlvaroS

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

AlvaroS

@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

@AlvaroS Then try what @mrjj suggested

AlvaroS

This post is deleted!

AlvaroS

@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

@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

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

mrjj

@AlvaroS

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

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

AlvaroS

@mrjj Yes:

    myProcess->start(program, arguments);

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

mrjj

@AlvaroS
hmm really odd then
it should say FailedToStart

Just to be 100% clear.

princi is never run ?

AlvaroS

@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

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.

AlvaroS

@mrjj Yes... I think so...
How should I pass the arguments?

the arguments of princi are:

0 wps.front().x() wps.front().y() 0 wps.back().x() wps.front().y() prueba_princi.bmp 0 0 +

so my QStringList arguments is:

 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" << "+" ;

mrjj

it seems fine
You should look inside princi for how it
reads it. it must be that part that is crashing ?