Call QProcess without GUI

[mattia]

Hi, what what should i write into the connect function to call the slot updateError() that is into the CallApplication class?
The connect function in not declared in this scope but i dont need that the callApplication.h derive by QMainWindow or something like that. Is there a work around?
i want just to call a extern process without any GUI.

callApplication.h

#include <QProcess>
 
class CallApplication 
{
public:
	CallApplication();
	~CallApplication();
	void performApplication();
private slots:
	void updateError();
    	void processFinished(int exitCode, QProcess::ExitStatus exitStatus);
    	void processError(QProcess::ProcessError error);
public:
	QProcess process;
};

#include <QProcess>

class CallApplication 
{
public:
	CallApplication();
	~CallApplication();
	void performApplication();
private slots:
	void updateError();
    	void processFinished(int exitCode, QProcess::ExitStatus exitStatus);
    	void processError(QProcess::ProcessError error);
public:
	QProcess process;
};

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callApplication.cpp

#include <callApplication.h>
 
CallApplication::CallApplication()
{
	connect(&process, SIGNAL(readyReadStandardError()), /*CallApplication*/, SLOT(updateError())); //<--the reciver is CallApplication
}
 
CallApplication::~CallApplication(){}
 
void CallApplication::performApplication()
{
	QStringList args;
	args << "-resize" << "100x100" << "/home/mattia/image1/1.jpg";
	process.start("mogrify", args);
}
void CallApplication::updateError(){}
 
void CallApplication::processFinished(int exitCode, QProcess::ExitStatus exitStatus)
{
}	
 
 
void CallApplication::processError(QProcess::ProcessError error)
{	
}

#include <callApplication.h>

CallApplication::CallApplication()
{
	connect(&process, SIGNAL(readyReadStandardError()), /*CallApplication*/, SLOT(updateError())); //<--the reciver is CallApplication
}

CallApplication::~CallApplication(){}

void CallApplication::performApplication()
{
	QStringList args;
	args << "-resize" << "100x100" << "/home/mattia/image1/1.jpg";
	process.start("mogrify", args);
}
void CallApplication::updateError(){}

void CallApplication::processFinished(int exitCode, QProcess::ExitStatus exitStatus)
{
}	


void CallApplication::processError(QProcess::ProcessError error)
{	
}

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[DeepDiver]

simply use: this

[mattia]

Do you mean in this way?

connect(&process, SIGNAL(readyReadStandardError()), this, SLOT(updateError()));

connect(&process, SIGNAL(readyReadStandardError()), this, SLOT(updateError()));

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I get this error: connect was not declered in this scope

[DeepDiver]

Try this:

QObject::connect(&process, SIGNAL(readyReadStandardError()), this, SLOT(updateError()));

QObject::connect(&process, SIGNAL(readyReadStandardError()), this, SLOT(updateError()));

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[mattia]

now i get the access at the connect function but something still wrong, i get this error:
no matching function for call to ‘QObject::connect(QProcess*, const char [26], CallApplication* const, const char [15])’

[jacek]

CallApplication doesn't inherit QObject and it lacks Q_OBJECT macro --- without this signals & slots mechanism won't work.

[mattia]

So, have i to declare the .h class in this way?

#include <QProcess>
 
      class CallApplication : public QObject
      {
       Q_OBJECT
      public:
          CallApplication();
          ~CallApplication();
          void performApplication();
      private slots:
          void updateError();
              void processFinished(int exitCode, QProcess::ExitStatus exitStatus);
              void processError(QProcess::ProcessError error); 
      public:
          QProcess process;
      };

#include <QProcess>
       
      class CallApplication : public QObject
      {
       Q_OBJECT
      public:
          CallApplication();
          ~CallApplication();
          void performApplication();
      private slots:
          void updateError();
              void processFinished(int exitCode, QProcess::ExitStatus exitStatus);
              void processError(QProcess::ProcessError error); 
      public:
          QProcess process;
      };

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[jacek]

So, have i to declare the .h class in this way?

Yes, and don't forget to re-run qmake.

[mattia]

Done! Now it's working. Thanks so much.