How we can connect the signals and slot with different arguments?

Question

In Qt, signals and slots require matching argument types:

QObject::connect: Incompatible sender/receiver arguments QLabel::linkActivated(QString) --> Butt

Answer 1

Default values for slot parameters helps very well. This allow to connect signals with different signatures to slot (vice versa to @pnezis answer):

private slots:
  void slot( int x = 10, int y = 20, QString text = QString() );

may be connected to different signals:

signal1(int, int, QString)
signal2(int, int)
signal3(int)
signal4()

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Also Qt 4.8 suggest useful QSignalMapper class:

This class collects a set of parameterless signals, and re-emits them with integer, string or widget parameters corresponding to the object that sent the signal.

But only for one parameter:

QSignalMapper* mapper = new QSignalMapper(this) ;

connect(action, SIGNAL(triggered()), mapper, SLOT(map())) ;
mapper->setMapping(action, "param value") ;

connect(mapper, SIGNAL(mapped(const QString &)),
  this, SIGNAL(clicked(const QString &)));