how to pass arguments to QTimer::singleshot slot

[Qt Enthusiast]

I can use QTimer as:
QTimer::singleShot(1500, this, SLOT(crossCapture()));

But, can this be used like:
QTimer::singleShot(1500, this, SLOT(crossCapture(int,int)));

Please not crossCapture will be executed in GUI main thread

[Gojir4]

No, you cannot.
You have to find another way to give the arguments when the "timeout" occurs.

I you are using threads, you can use dedicated signal-slots to communicate with you GUI.

[Qt Enthusiast]

howabout using std::bind features of c++ , if you can guide a litthle bit

[Pablo J. Rogina]

@Qt-Enthusiast what are the two integers you expect? I guess singleShot() is not aware of what you'll need. So you may need an indirect call, some pseudo-code here:

QTimer::singleShot(1500, this, SLOT(crossCapture()));
...
void crossCapture() {
     int x = getMousePointerX();
     int y = getMousePointerY();
     crossCapture(x, y);
}

void crossCapture(int x, int y) {
    // do the actual task
}

[VRonin]

Assuming decltype(this)==MyClass*:
QTimer::singleShot(1500, this, std::bind(&MyClass::crossCapture,this,88,11));

[Pablo J. Rogina]

@VRonin sorry for asking, but how would you write to sentence to work dynamically? (not having constant values)

[VRonin]

@Pablo-J.-Rogina You can still use a lambda: QTimer::singleShot(1500, this, [this]()->void{crossCapture(getMousePointerX(),getMousePointerY());});

[kshegunov]

Or:

QTimer::singleShot(1500, this, std::bind(&MyClass::crossCapture, this, getMousePointerX(), getMousePointerY()));

But there's a very distinct difference between what @VRonin wrote and the above line. So in general they are not going to behave the same.

[Qt Enthusiast]

@kshegunov said in how to pass arguments to QTimer::singleshot slot:

QTimer::singleShot(1500, this, std::bind(&MyClass::crossCapture, this, getMousePointerX(), getMousePointerY()));

It is giving me compilation error

I will let you know in Detail

I have a a function name

class myClass{
public:
void F(int argc,const char* argv[],char* msg,bool &done);
};

void myClass::F(int argc,const char* argv[],char* msg,bool &done) {
/ using argc and argv
msg = "Message"
done = true;
}

now I have to call the same using QTimer::single shot

std::function<void(int ,const char* ,char* ,bool &> f = std::bind(&myClass::F, this, _1,_2,_3,_4) ;

QTimer::singleshot(0,this,SLOT(f());

it is not working , can some one correct my code

[VRonin]

@Qt-Enthusiast said in how to pass arguments to QTimer::singleshot slot:

msg = "Message"

This is assigning the address of a local constant so doesn't work

this,SLOT(f());

We never used SLOT above, why did you decide to add it? QTimer::singleshot(0,this,f);

_1,_2,_3,_4

What is supposed to fill those?