CODEWITHSUNDEEP
qtqt4environment-variablesqprocess
Shen Chen
Shen Chen

Reputation: 123

Set Environment Variables for startDetached() QProcess

In Qt4, there is QProcess::setProcessEnvironment() for setting Env variables for the newly spawn process.

However, QProcess::startDetached() is a static member function, so setProcessEnvironment() doesn't apply. How does one set Env variables for a detached process in Qt?

Upvotes: 4

Views: 6073

Answers (3)

Bowdzone
Bowdzone

Reputation: 3864

This behaviour has been fixed in Qt 5.10.0. However, the order of calls seems to be important. The following example works:

QProcess proc;
QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
env.insert("var-name", "var-value");
proc.setProgram("program-path");
proc.setProcessEnvironment(env);
proc.startDetached();

while this does not work:

QProcess proc;
QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
env.insert("var-name", "var-value");
proc.setProcessEnvironment(env);
proc.startDetached("program-path");

Upvotes: 3

Giuseppe Cardone
Giuseppe Cardone

Reputation: 5393

It is a known old bug: http://bugreports.qt-project.org/browse/QTBUG-2284. You need to overload startDetached function to support your own environment. Take a look at Qt sources to see how to do that: http://code.qt.io/cgit/qt/qtbase.git/tree/src/corelib/io?h=5.5 (qprocess* files).

Upvotes: 3

Ian.Zhang
Ian.Zhang

Reputation: 171

Using Qt5.5 now, Run into this problem.

Under Win7, Used code below, Set environment in father process, It seems that sub process inherit the environment. Not for sure, but it worked in my case.

Hope there is better solutions

QString oldPath = qgetenv( "Path" );
QByteArray newPath = ( QCoreApplication::applicationDirPath() + ";" + oldPath ).toLocal8Bit();
bool bSet = qputenv("Path", newPath);
if ( !bSet )
{
    qDebug()<<"Failed";
}

Upvotes: 0

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