problem with System()

[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 ?

[AlvaroS]

@mrjj yes, but it really rare that if I run from terminal princi runs good...

[AlvaroS]

@mrjj And if I write:

system ("./princi 0 5 10 0 7 8 prueba_princi.bmp 0 0 +")
where 5,10,7 and 8 are wps.front,wps.back....
it runs well...

[SGaist]

What is that + sign doing as parameter ?

[AlvaroS]

@SGaist + is just and argument that i have to pass to princi

[mrjj]

@AlvaroS
well you must debug it then.
Try to qDebug inside princi what you read and compare that to what u read for
system ("./princi 0 5 10 0 7 8 prueba_princi.bmp 0 0 +")

Sadly We cannot guess why you crash from the code shown.

Also you dump the arguments to qDebug before u
call start, just to see what u are sending also.

and then take it from there.