What does :: means before function deceleration?

Development Programming & Scripting
1

So i switch from unity to unreal and C++ is really giving me a hard time. I cant understand​ that what is the purpose of :: before a function deceleration or definition for example
My class name is test
So what does void test:: myfunction(){
//Lines of code
}
means?(i know what void is though)
And in unreal these functions are also called every frame how is that possible?
I mean in unity you have to put everything in update() function to execute it every frame but in unreal many functions are automatically called
Please need help
Ps i thought :: was used for calling only the static variabels or functions if a class but need a help with this
Thanks in advance

2

:: is known as the scope resolution operator.
Classes behave almost like namespaces. Now when you define a function in your class, it’s a member of your class.

class foo
{
  public:
    void yourfunc();
}

here foo is your class with a member (function) called yourfunc(). Because you declare your functions outside of your header file, you have to tell your compiler, where your function is. In our situation it’s member off foo so we write:

foo::yourfunc()
{
    // Your code...
}

Source: click here