Question

When using Qt, many functions take an argument like the flag Qt::LeftDockWidgetArea.

Even though I looked through the Qt sources I could not understand how to achieve
this naming behaviour. Is it general C++ or Qt specific?

Assume I have a class MyClass:

class MyClass {
    public:
        MyClass();
        void setFlag(???);
};

I want to call the setFlag method like this:

MyClass mc;
mc.setFlag(MyClass::flag1 | MyClass::flag2)

flag1 and flag2 should just be 0x01 & 0x02, is this an enum?
Where do I have to declare that?
And what is the argument of the method?

I’m sorry if this is obvious, but I don’t get it.

SOLUTION (from the answers)

Very good. From reading the answers below I added this:
(note that I didn’t really needed flags, just the numbers from an enum, this simplified it a lot)

namespace MyNames {
    typedef enum {
        FA = 0,
        FB = 1
    } Field;
}

class MyClass
{
    public:
        MyClass();
        char getField(MyNames::Field f) const;
};

This indeed allows the following calls (not):

mc.getField(MyNames::FA) //OK
mc.getField(1)           //not OK

Answer 1

You will find this (or something similar) in src\corelib\global\qnamespace.h:

#ifndef Q_MOC_RUN
namespace
#else
class Q_CORE_EXPORT
#endif
Qt {

This usually becomes simply

namespace Qt {

To refer to a name declared inside this Qt namespace (such as LeftDockWidgetArea), you precede it with Qt::.