signal/slot different approach

[salmanmanekia]

what's the difference between the two declaration below

connect(object1,SIGNAL(clicked()),SIGNAL(mySignal( )));

connect(object1,SIGNAL(clicked()),this,SLOT(mySlot ()));
void mySlot()
{
emit mySignal();
}
which is preferred and why..

[spirit]

what's the difference between the two declaration below

connect(object1,SIGNAL(clicked()),SIGNAL(mySignal( )));

connect(object1,SIGNAL(clicked()),this,SLOT(mySlot ()));
void mySlot()
{
emit mySignal();
}
which is preferred and why..

the third parameter (this) is the receiver, if reciver isn't specify than an object, in which connect is used, is used by default.

[wysota]

which is preferred and why..

First one is cleaner and will be one invokation faster than the other.

[salmanmanekia]

First one is cleaner and will be one invokation faster than the other.
can you please elobrate on 'invokation'

[lyuts]

what's the difference between the two declaration below

connect(object1,SIGNAL(clicked()),SIGNAL(mySignal( )));

connect(object1,SIGNAL(clicked()),this,SLOT(mySlot ()));
void mySlot()
{
emit mySignal();
}
which is preferred and why..

The difference is that the first connect connects a signal to another signal (with "this" as a receiver). It means that mySignal will be emited as soon as clicked signal emits. I think usually further action would be to connect mySignal to a slot (just like the 2nd connect statement).

[wysota]

can you please elobrate on 'invokation'

Function call. Signal emition is a function call and so is slot activation, so if you don't activate the slot and instead emit the signal directly, you'll have one function call less (which is probably saving about up to 20 cpu cycles, so it's completely irrelevant).