Calling external programs?

[jpn]

That part was just a paste. I looked at the constructor again, and it seems all arguments are optional. If I change it to

proc=new QProcess();

proc=new QProcess();

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At least that error disappeared.

Every QObject (QProcess is a QObject) takes a parent parameter for a reason. Make sure to pass a proper parent or delete the object yourself. Otherwise you'll get a memory leak.

Now I got an even worse one.

mainwindow.cpp: In member function ‘void mainwindow::doit()’:
mainwindow.cpp:33: error: could not convert ‘((mainwindow*)this)->mainwindow::proc-> QProcess::start(((const QString&)((const QString*)(& program))), ((const QStringList&)((const QStringList*)(& arguments))), QFlags<QIODevice::OpenModeFlag>(ReadWrite))’ to ‘bool’

mainwindow.cpp: In member function ‘void mainwindow::doit()’:
mainwindow.cpp:33: error: could not convert ‘((mainwindow*)this)->mainwindow::proc-> QProcess::start(((const QString&)((const QString*)(& program))), ((const QStringList&)((const QStringList*)(& arguments))), QFlags<QIODevice::OpenModeFlag>(ReadWrite))’ to ‘bool’

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Take a closer look at QProcess::start() docs. It's a void function. No bool is returned.