Retrieve environment variables of a QProcess

Question

I want to run an environment script within a QProcess and then read the environment (as a QStringList) to start other scripts with this environment.

If I start the env script and read the environment, I always get an empty QStringList. Is there a way to read out the environment of a QProcess?

I also tried to first start the environment script and the start the actual script on the same QProcess object but that did not help either.

Answer 1

If you are able to rewrite the script which sets the environment in C++ you can create the environment yourself and set it using
void QProcess::setProcessEnvironment ( const QProcessEnvironment & environment ) method as in the example given in the method's documenation:

 QProcess process;
 QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
 env.insert("TMPDIR", "C:\\MyApp\\temp"); // Add an environment variable
 env.insert("PATH", env.value("Path") + ";C:\\Bin");
 process.setProcessEnvironment(env);
 process.start("myapp");

UPDATE

If you can't use the above method you could try using cmd.exe like this;

#include <QtCore/QCoreApplication>
#include <QtCore/QProcess>

int main(int argc, char *argv[])
{
    QCoreApplication app(argc, argv);

    QProcess* proc = new QProcess();
    proc->start("cmd.exe /c \"call env.bat && script.bat\"");

    return app.exec();
}

Having env.bat with this contents

set abc=test

and script.bat with this contents

echo %abc% > a.txt

running the above creates a.txt file with this contents

test 

Answer 2

If you haven't used QProcess's setEnvironment method, then the empty QStringList is the expected output. For this case, QProcess uses the program's environment. To get this,

QStringList env(QProcess::systemEnvironment());

should work.