() syntax when passing as argument to function

[stridder]

Hello,
What is the syntax '()' e.g in 'ZeroFunction<2>()' when it is passed as argument to a function.
ZeroFunction is a class. Is it a call of constructor?
If so, then what happens when it is passed to a function?
Here is a code example:

interpolate_boundary_values (dof_handler,0, ZeroFunction<2>(), boundary_values); 

Thank you.

[firedraco]

If ZeroFunction is a class, yes it would call the constructor.

It is basically the same as:

ZeroFunction<2> tmp;
interpolate_boundary_values (dof_handler,0, tmp, boundary_values);

[stridder]

Thank you!