Get output of Qprocess in a variable?

Question

This question is similar to this one. The difference is that the solution specified there doesn't work always.

Example 1

QProcess * process;
process = new QProcess();
process->start("/usr/bin/env");
process->waitForFinished(-1);

QString p_stdout = process->readAllStandardOutput();
qDebug() << p_stdout;

//output
HOME=/home
PATH=/usr/bin:/bin:/usr/sbin:/sbin:/sbin:/usr/sbin
DISPLAY=:0.0
SHELL=/bin/sh
PWD=/home

Everything works, and the output is like typing /usr/sbin/env in the terminal.

Example 2

QProcess * process;
process = new QProcess();
process->start("/usr/sbin/iptables");
process->waitForFinished(-1);

QString p_stdout = process->readAllStandardOutput();
qDebug() << p_stdout;

//output
""

Same code, just a different command and no output. There is output when i type /usr/sbin/iptables in the terminal

iptables v1.4.16.3: no command specified Try `iptables -h' or 'iptables --help' for more information.

bit it doesn't appear in p_stdout. What is the catch with this solution?

Have you tried connecting to the error signal in QProcess and reading from standard error? — TheDarkKnight, Feb 07 '14 at 13:33
@vahancho Yes, that was the problem. I've solved it with `process->setProcessChannelMode(QProcess::MergedChannels);` — TheMeaningfulEngineer, Feb 07 '14 at 14:46
Alan, it's perfectly fine to answer your own question. Write your solution as an answer, and delete the comment. You should then also flag my comment and all the other comments as obsolete (since they will be, then!). — Kuba hasn't forgotten Monica, Feb 07 '14 at 16:21

Get output of Qprocess in a variable?

0 Answers0