Altering QProcess environment

[shaolin]

Hi guys,

I have to start ffmpeg from within my program, under Os X. It's installed via macports, so the executable file is in /opt/local/bin/ffmpeg. I'm trying to do this:

QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
    env.insert("PATH", env.value("PATH") + ":/opt/local/bin");
    env.insert("PATH", env.value("PATH") + ":/opt/local/sbin");
    this->ffmpegProcess.setProcessEnvironment(env);

QProcessEnvironment env = QProcessEnvironment::systemEnvironment();
    env.insert("PATH", env.value("PATH") + ":/opt/local/bin");
    env.insert("PATH", env.value("PATH") + ":/opt/local/sbin");
    this->ffmpegProcess.setProcessEnvironment(env);

To copy to clipboard, switch view to plain text mode 

After this I print the environment variables of the process with:

QStringList environment = ffmpegProcess.processEnvironment().toStringList();
        for(int i=0; i < environment.size(); i++){
            std::cout << environment.at(i).toLocal8Bit().constData() << std::endl;
        }

QStringList environment = ffmpegProcess.processEnvironment().toStringList();
        for(int i=0; i < environment.size(); i++){
            std::cout << environment.at(i).toLocal8Bit().constData() << std::endl;
        }

To copy to clipboard, switch view to plain text mode 

and in effect, I obtain:

QTDIR=/usr/local/Qt4.7
PATH=/Developer/Tools/Qt:/usr/bin:/bin:/usr/sbin:/sbin:/opt/local/bin:/opt/local/sbin
TMPDIR=/var/folders/Do/DoA9CZUOFWa0g8wPOe-FYk+++TI/-Tmp-/
etc...

QTDIR=/usr/local/Qt4.7
PATH=/Developer/Tools/Qt:/usr/bin:/bin:/usr/sbin:/sbin:/opt/local/bin:/opt/local/sbin
TMPDIR=/var/folders/Do/DoA9CZUOFWa0g8wPOe-FYk+++TI/-Tmp-/
etc...

To copy to clipboard, switch view to plain text mode 

So, now the PATH is ok, but if I try to start ffmpeg WITHOUT prepending "/opt/local/bin/" it doesn't work.

Any suggestion?
Thx in advance

[wysota]

It's not how it works. You need to alter your own environment (qputenv) to make it possible that YOUR application can find some other application in its path. The environment you set for the process becomes effective only when the process is already being (successfully) launched.

[shaolin]

So to set the PATH variable, for example, I should use qputenv(). Can I use

QProcessEnvironment env = QProcessEnvironment::systemEnvironment();

QProcessEnvironment env = QProcessEnvironment::systemEnvironment();

To copy to clipboard, switch view to plain text mode 

as in the previous code to get the existing PATH variable, or should I use qgetenv()?

[wysota]

You can do either. Using qgetenv/qputenv is probably simpler as you only want to retrieve one variable.