Using system command in Qt

Question

How can I use the system command where the command is written in a QString?

Like:

QString command="chmod -R 777 /opt/QT/examples/code/TestGUI/Data";    
system(command);

While compiling, I get this error:

cannot convert ‘QString’ to ‘const char*’
  for argument ‘1’ to ‘int system(const char*)’

Can anyone suggest something?

possible duplicate of [QString to char conversion](http://stackoverflow.com/questions/2523765/qstring-to-char-conversion) — Mat, May 29 '12 at 12:16

score 12 · Answer 1 · answered May 29 '12 at 12:52

12

Use the qPrintable() macro

system(qPrintable(command));

answered May 29 '12 at 12:52

Vinicius Kamakura

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Hey, thanks! I didn't know about `qPrintable`. One learns something every day. – Kuba hasn't forgotten Monica May 31 '12 at 20:04

score 8 · Answer 2 · answered May 29 '12 at 12:21

8

You need get the raw character array from the QString. Here is one way:

system(command.toStdString().c_str());

answered May 29 '12 at 12:21

Jason B

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score 7 · Answer 3 · edited Sep 18 '15 at 06:12

7

Ankur Gupta wrote, use QProcess static function (link to description):

int QProcess::execute ( const QString & program )

In your situation:

QProcess::execute ("chmod -R 777 /opt/QT/examples/code/TestGUI/Data");

edited Sep 18 '15 at 06:12

Christophe Weis

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answered May 29 '12 at 13:04

firescreamer

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score 6 · Answer 4 · edited Sep 18 '15 at 06:34

6

QProcess class http://doc.qt.io/qt-5/qprocess.html. It's what you need.

edited Sep 18 '15 at 06:34

Christophe Weis

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answered May 29 '12 at 12:16

Ankur Gupta

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score 0 · Answer 5 · answered Sep 13 '12 at 14:07

0

To change permission you could use setPermissions of QFile

answered Sep 13 '12 at 14:07

Vlad Gordin

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score 0 · Answer 6 · answered Nov 15 '13 at 09:05

0

you can convert QString to const char*.

if your string is in UTF8, then you can use:

const char* my_command = command.toUtf8().constData() ;
system(my_command);

else if your string is not in UTF8, then you can use:

command.toLatin1().constData() ;
system(my_command);

in this case second one is what you want.

answered Nov 15 '13 at 09:05

AliS

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I kno0w this post is ancient , but QProcess::execute ("service bluetooth status"); "forwards results to calling process" -- HOW to write a C++ code to accomplish such "forwarding"? – Jan 19 '23 at 15:54

Using system command in Qt

6 Answers6