QFlags usage

Anonymous_Banned275

**EDIT

This is a bad idea , please ignore BEFORE I delete it.**

I am going to utilize QFlags to identify specific class / object.

I am looking into this example to define my own flags

https://doc.qt.io/qt-6/qflags.html#details

class MyClass
{
public:
    enum Option {
        NoOptions = 0x0,
        ShowTabs = 0x1,
        ShowAll = 0x2,
        SqueezeBlank = 0x4
    };
    Q_DECLARE_FLAGS(Options, Option)
    ...
};

Q_DECLARE_OPERATORS_FOR_FLAGS(MyClass::Options)

and I do not understated where to define this "custom flags " optional class MyClassclass.

I like to identify my objects which are used as a library in my subdirs project .

Hence I would prefer to have the this optional class MyClassclass as as a library so it can be used / accessed by
them.

ChrisW67

Does MyClass contain anything other than the enum and two related Q_* macros?

If it is only that, then the class is entirely self-contained in the header (all the needed functions to support QFlag are inlined) and there are no sources to add to a library project. Assuming that other things in your library use MyClass, the header should be part of the headers that go with the library. A user of MyClass can create an instance after including the header.

If there is any other non-inlined code in the MyClass then its corresponding source file should be included in the library. A user of MyClass needs to include the header in their source and link the library before they can create an instance of the class.

Asperamanca

@AnneRanch
You can also use QFlags on enums outside classes, and better still, on scoped enums, like so:

enum class EMyOption : int
{
    NoOptions = 0x0,
    ShowTabs = 0x1,
    ShowAll = 0x2,
    SqueezeBlank = 0x4
};
Q_DECLARE_FLAGS(MyOptions, EMyOption)

Q_DECLARE_OPERATORS_FOR_FLAGS(MyOptions)
Q_DECLARE_METATYPE(EMyOption)
Q_DECLARE_METATYPE(MyOptions)

That's header-only - no need for a source file.