How to communicate with external programs?

[jacek]

Canyou suggest a better method to do this task.

Use QProcess::startDetached(). This should work:

QProcess::startDetached( "start", QStringList() << "something.jpg" );

QProcess::startDetached( "start", QStringList() << "something.jpg" );

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Secondly I need to create , open , write , execute and close the file very often in my program on the click of buttons.

Use QProcess.

Please, don't ask unrelated questions in one thread --- open new thread for new issues. Also, please, use [ code ] tags for code snippets and [ quote ] tags only for quotes.

[deekayt]

Suppose I need to start any program which is there available in my computer by click of button from my designed form.
I have created a QDialog and put a pushbutton. Then through a private slot I am trying to access the program ( or launch the program , say windows media player which is “wmplayer” ) which ideally should be detached from the parent program which I launch initially .
I have tried QProcess with various combinations but it is not working.
Where as if you type wmplayer on the command line run window the program runs.
Interestingly when I type “cmd” that is the command line window it runs from myprogram and the command prompt for DOS opens up .But this is theonlyone which runs.

The code is as

steg::steg(QWidget *parent)
     : QDialog(parent)
 {
     ui.setupUi(this);  
      connect(ui.showdatafile, SIGNAL(clicked()), this, SLOT(showdatafile()));
 
 }
 
void steg::showdatafile()
{  
    QProcess *myProcess ;    
    QString program = "wmplayer";        
    myProcess->startDetached(program);
}

steg::steg(QWidget *parent)
     : QDialog(parent)
 {
     ui.setupUi(this);  
      connect(ui.showdatafile, SIGNAL(clicked()), this, SLOT(showdatafile()));

 }

void steg::showdatafile()
{  
    QProcess *myProcess ;    
    QString program = "wmplayer";        
    myProcess->startDetached(program);
}

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I have tried your suggestion also

QProcess::startDetached( "start", QStringList() << "something.jpg" );

QProcess::startDetached( "start", QStringList() << "something.jpg" );

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the code doesnot give any error.But when I click the button to launch it just doesnot run at all
could you suggest some solution

[patrik08]

Have a look on
http://www.qtcentre.org/forum/f-qt-p...-doc-4178.html

running only on mac & win .. linux dont have system urlhandler or file ecc...
only webbsiteurl on the new QDesktopServices qt4.2

[jacek]

myProcess->startDetached(program);

QProcess::startDetached is a static method, you don't need any object to invoke it.

How about this?

QProcess::startDetached( "C:/full/path/to/wmplayer", QStringList() );

QProcess::startDetached( "C:/full/path/to/wmplayer", QStringList() );

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Also check the return value.

[jacek]

char encrypt_comand[]= " -e ";
char key_comand[]= "-k=";
char space[]= " ";

QProcess p3;
QStringList s3;
s3 << space<< encrypt_comand<<ui.datalineEdit->text() <<space<< "coded.txt"<<space<<key_comand <<ui.passphraselineEdit->text();
p3.startDetached(QString("burp.exe") , s3 );
}

Each entry in the string list "s3" should represent a single argument, so you shouldn't add any spaces, especially inside encrypt_command.

It should be something like (note the + after key_command):

char encrypt_comand[]= "-e";
char key_comand[]= "-k=";
 
QStringList s3;  
s3 << encrypt_comand << ui.datalineEdit->text() << "coded.txt" << ( key_comand + ui.passphraselineEdit->text() );
QProcess::startDetached( QString("/full/path/to/burp.exe"), s3 );

char encrypt_comand[]= "-e";
char key_comand[]= "-k=";

QStringList s3;  
s3 << encrypt_comand << ui.datalineEdit->text() << "coded.txt" << ( key_comand + ui.passphraselineEdit->text() );
QProcess::startDetached( QString("/full/path/to/burp.exe"), s3 );

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Make sure you specify full path to the executable, if it isn't in the current working directory (you might find QCoreApplication::applicationDirPath() useful).

And, for the second time, QProcess::startDetached() is a static method, so you shouldn't create any QProcess instances to invoke it.

Edit: Please, don't ask the same question in more than one thread. Threads merged.