Functionality of void operator()()

Question

I am confused about the functionality of void operator()().

Could you tell me about that, for instance:

class background_task
{
public:

            


        

Answer 1

The first () is the name of the operator - it's the operator that is invoked when you use () on the object. The second () is for the parameters, of which there are none.

Here's an example of how you would use it:

background_task task;
task();  // calls background_task::operator()