c++ how to have same enum members name in different enum names without getting err:redefinition; previous definition was 'enumerator'

Question

I have config file that I include in all my files there I have different enums but inside each enum there are same element names for example: config.h

enum GameObjectType
{
     NINJA_PLAYER

};
enum GameObjectTypeLocation
{
    NONE,
    MASSAGE_ALL,  //this is for ComponentMadiator
    NINJA_PLAYER


};

But when I try to compile the project with calling the enums with the proper enum name

m_pNinjaPlayer = (NinjaPlayer*)GameFactory::Instance().getGameObj(GameObjectType::NINJA_PLAYER);
    ComponentMadiator::Instance().Register(GameObjectTypeLocation::NINJA_PLAYER,m_pNinjaPlayer);

I am getting compilation error:

error C2365: 'NINJA_PLAYER' : redefinition; previous definition was 'enumerator' (..\Classes\GameFactory.cpp)
2>          d:\dev\cpp\2d\cocos2d-x-3.0\cocos2d-x-3.0\projects\lettersfun\classes\config.h(22) : see declaration of 'NINJA_PLAYER'

How can I keep in the config.h several enums with different names BUT with same elements names ?

juanchopanza · Accepted Answer · 2014-04-25T09:25:51.170

59

The problem is that old-style enumerations are unscoped. You can avoid this problem (provided your compiler has the relevant C++11 support) by using scoped enumerations:

enum class GameObjectType { NINJA_PLAYER };

enum class GameObjectTypeLocation { NONE, MASSAGE_ALL, NINJA_PLAYER };

Alternatively, you can put your old-school enumerations in namespaces:

namespace foo
{
  enum GameObjectType { NINJA_PLAYER };
} // namespace foo

namespace bar
{
  enum GameObjectTypeLocation { NONE, MASSAGE_ALL, NINJA_PLAYER };
} // namespace bar

Then your enum values will be foo::NINJA_PLAYER, bar::NINJA_PLAYER etc.

edited Apr 25 '14 at 09:25

answered Apr 25 '14 at 09:17

juanchopanza

223,364
34
402
480

1

Thanks didn't know c++ 11 can use class in enums – user63898 Apr 25 '14 at 13:16
1

@diego.martinez It is not OS dependent. It is a C++ thing. – juanchopanza Apr 04 '17 at 14:59
@juanchopanza sorry, I meant that while my visual studio 2012 compiles just fine, gcc throws errors. – diego.martinez Apr 05 '17 at 15:41
1

According to [this answer](https://stackoverflow.com/a/8357366/4669135) the `namespace` hack to scope standard enums seems to be the only solution **if you do not want to use enum class** because of their need of `static_cast` to get an integer value. – Gabriel Devillers Jul 21 '17 at 10:05

score 12 · Answer 2 · answered Apr 25 '14 at 09:17

12

If you have the possibility to use C++11 I would recommend to use enum class feature to avoid collisions:

enum class GameObjectType
{
     NINJA_PLAYER

};
enum class GameObjectTypeLocation
{
    NONE,
    MASSAGE_ALL,  //this is for ComponentMadiator
    NINJA_PLAYER


};

Edit: If you do not have this ability, then you will need to use two different namespaces for each enum.

answered Apr 25 '14 at 09:17

Samuel

6,126
35
70

1

Two different namespaces, or wrap each enum with a class. – James Kanze Apr 25 '14 at 09:28

c++ how to have same enum members name in different enum names without getting err:redefinition; previous definition was 'enumerator'

2 Answers2

Linked

Related