Singleton problems

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12-31-2004
techrolla

Singleton problems

I posted a question similar to this one before, but it seemed to die out.

Here is my problem: I have two classes using a singleton design pattern, and everything works fine. For our purposes one of the classes is called GameManager. The problem comes when I try to get the static instance of the GameManager from another class, let's say, Camera. I get a lot of parse errors before "*" from g++. Here are the parts of Camera and GameManager that i believe are causing problems:

GameManager.h

Code:

#ifndef AC_GAMEMANAGER_H_ #define AC_GAMEMANAGER_H_ #ifdef _WINDOWS #include <windows.h> #endif #include <GL/gl.h> #include <GL/glu.h> #include <math.h> #include "SDL.h" #include "types.h" #include "UIManager.h" #include "Error.h" #include "Scene.h" #include "Keys.h" class GameManager { static GameManager *_instance; UIManager *uimanager; Scene scene; Keys keys; ac_int init(ac_void); ac_void loopGame(ac_void); ac_void renderScene(ac_void); GameManager() {} public: static GameManager *instance(ac_void); ac_void beginGameLoop(ac_void); /* Get and Set */ /** * @return the <code>Scene</code> object */ Scene getScene(ac_void) const { return scene; } /** * @return the <code>Keys</code> object */ Keys getKeys(ac_void) { return keys; } }; #endif /* AC_GAMEMANAGER_H_ */

And the instance function for the GameManager:

Code:

GameManager *GameManager::_instance = 0; GameManager *GameManager::instance() { if (!_instance) { _instance = new GameManager(); _instance->init(); } return _instance; }

Here are the problem parts in Camera:

Camera.h

Code:

#ifndef AC_CAMERA_H_ #define AC_CAMERA_H_ #include <GL/gl.h> #include <GL/glu.h> #include <stdio.h> #include "SDL.h" #include <math.h> #include "UIManager.h" #include "GameManager.h" #include "MainFrame.h" #include "Keys.h" #include "Error.h" #include "version.h" class Camera { /* ... */ GameManager *gameManager; public: /* ... */ }; #endif

And the places I use the gameManager in the Camera.cpp file:

Code:

Camera::Camera() { /* ... */ gameManager = GameManager::instance(); } /** And inside a movement function: */ if(gameManager->getKeys().isActionDown("+forward")) { MoveCamera(speed); }

Here is the compiler output:

Code:

cd '/home/max/programming/c++/gl/angelchronicles/angelchronicles/debug' && WANT_AUTOCONF_2_5="1" WANT_AUTOMAKE_1_6="1" gmake -k -j1 compiling angelchronicles.cpp (g++) /home/max/programming/c++/gl/angelchronicles/angelchronicles/src/Camera.h:104: error: syntax error before `*' token compiling LoadManager.cpp (g++) /home/max/programming/c++/gl/angelchronicles/angelchronicles/src/Camera.h:104: error: syntax error before `*' token compiling Game.cpp (g++) /home/max/programming/c++/gl/angelchronicles/angelchronicles/src/Camera.h:104: error: syntax error before `*' token compiling GameManager.cpp (g++) /home/max/programming/c++/gl/angelchronicles/angelchronicles/src/Camera.h:104: error: syntax error before `*' token compiling Camera.cpp (g++) /home/max/programming/c++/gl/angelchronicles/angelchronicles/src/GameSceneRender.h:29: error: ' Camera' is used as a type, but is not defined as a type. compiling Scene.cpp (g++) /home/max/programming/c++/gl/angelchronicles/angelchronicles/src/GameManager.h:43: error: ' Scene' is used as a type, but is not defined as a type. /home/max/programming/c++/gl/angelchronicles/angelchronicles/src/GameManager.h:63: error: parse error before `)' token /home/max/programming/c++/gl/angelchronicles/angelchronicles/src/GameManager.h:68: error: ISO C++ forbids defining types within return type /home/max/programming/c++/gl/angelchronicles/angelchronicles/src/GameManager.h:68: error: syntax error before `(' token compiling GameSceneRender.cpp (g++) /home/max/programming/c++/gl/angelchronicles/angelchronicles/src/Scene.h:51: error: syntax error before `*' token *** Exited with status: 2 ***

Note: The problem goes away when I don't use GameManager in Camera.

Thanks alot, and if you need more code just ask. Any suggestions? Thanks!
12-31-2004
B0bDole

>The problem goes away when I don't use GameManager in Camera.

then don't
01-01-2005
techrolla

Well that would be the easy way out, but then I don't get the functionality that I need. But is there a reason that this is happening? Am I approaching the singleton in the wrong way? Thanks.
01-01-2005
Sebastiani

try placing this line in GameManager.h instead of GameManager.cpp:

>> GameManager *GameManager::_instance = 0;
01-01-2005
techrolla

No change, I am afraid to say.

Could it possibly be that I have the first instance of GameManager created in a non-class as a global?

Here is my game.h file:

Code:

#ifndef AC_GAME_H_ #define AC_GAME_H_ #include "types.h" #include "UIManager.h" #include "GameManager.h" extern UIManager *uimanager; extern GameManager *gamemanager; /** * Start the game by initializing the UIManager and the * GameManager, the two classes that handle the majority of * the game. * @return any init codes */ ac_int startGame(ac_void); #endif /* AC_GAME_H_ */

And Game.cpp

Code:

#include "Game.h" #include "Error.h" UIManager *uimanager; GameManager *gamemanager; /* Start the whole game. Begin * by initializing the UIManager, then * the GameManager while will begin the event * loop. */ ac_int startGame(ac_void) { //UIManager *uimanager; //GameManager *gamemanager; uimanager = UIManager::instance(); gamemanager = GameManager::instance(); gamemanager->beginGameLoop(); return AC_INIT_SUCCESS; }
01-01-2005
Sebastiani

>> Could it possibly be that I have the first instance of GameManager created in a non-class as a global?

that shouldn't matter. I even wrote a test application to duplicate the problem, but everything worked fine. :confused: not sure what the problem is...
01-01-2005
techrolla

Here is a package of all the code I have right now, maybe I am missing something else where...There are makefiles and everything included for linux, the win32 stuff is old in the package. Here is the link:
http://max.muffinpeddler.com/arch/an...200511.tar.bz2

Thanks so much for your help.
01-01-2005
Da-Nuka

Have you tested if it works on any other compilers? :confused:
01-01-2005
Da-Nuka

Another thing, but thats not a error I think, just me who dont know much about C++ ;)

but this sentence:

GameManager() {}

What does it do?
It looks to me like its calling the function but.. what does the two block-marks do? ( { } )
and why dont they need a ";" after them to finish the sentence? :confused:

EDIT:
Hmm..wait wait wait.. Its a function declaration? :rolleyes:
01-01-2005
techrolla

The GameManager() {} just defines the default constructor, but it doesn't do anything. I may add to it later, but for now no.

Here is the vc++ 6 compiler output. Please disregard the opengl header errors, I need to add windows.h to the files:

Code:

--------------------Configuration: win32 - Win32 Debug-------------------- Compiling... angelchronicles.cpp c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\camera.h(106) : error C2143: syntax error : missing ';' before '*' c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\camera.h(106) : error C2501: 'GameManager' : missing storage-class or type specifiers c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\camera.h(106) : error C2501: 'gameManager' : missing storage-class or type specifiers Error.cpp Game.cpp c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\camera.h(106) : error C2143: syntax error : missing ';' before '*' c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\camera.h(106) : error C2501: 'GameManager' : missing storage-class or type specifiers c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\camera.h(106) : error C2501: 'gameManager' : missing storage-class or type specifiers LoadManager.cpp c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\camera.h(106) : error C2143: syntax error : missing ';' before '*' c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\camera.h(106) : error C2501: 'GameManager' : missing storage-class or type specifiers c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\camera.h(106) : error C2501: 'gameManager' : missing storage-class or type specifiers MainFrame.cpp Prefs.cpp UIManager.cpp Camera.cpp c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\gamescenerender.h(29) : error C2146: syntax error : missing ';' before identifier 'camera' c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\gamescenerender.h(29) : error C2501: 'Camera' : missing storage-class or type specifiers c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\gamescenerender.h(29) : error C2501: 'camera' : missing storage-class or type specifiers FreeType.cpp c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\freetype.cpp(364) : warning C4786: 'std::reverse_iterator<std::basic_string<char,std::char_traits<char>,std::allocator<char> > const *,std::basic_string<char,std::char_traits< char>,std::allocator<char> >,std::basic_string<char,std::char_traits<char>,std::allocator<char> > const &,std::basic_string<char,std::char_traits<char>,std::allocator<char> > const *,int>' : identifier was truncated to '255' characters in the debug information c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\freetype.cpp(364) : warning C4786: 'std::reverse_iterator<std::basic_string<char,std::char_traits<char>,std::allocator<char> > *,std::basic_string<char,std::char_traits<char>, std::allocator<char> >,std::basic_string<char,std::char_traits<char>,std::allocator<char> > &,std::basic_string<char,std::char_traits<char>,std::allocator<char> > *,int>' : identifier was truncated to '255' characters in the debug information GameManager.cpp c:\program files\microsoft visual studio\vc98\include\vector(39) : warning C4786: 'std::vector<std::basic_string<char,std::char_traits<char>,std::allocator<char> >,std::allocator<std::basic_string<char,std::char_traits<char>,std::allocator<char> > > >::vector<std::basic_string<char,std::char_traits<char>,std::allocator<char> >,std::allocator<std::basic_string<char,std::char_traits<char>,std::allocator<char> > > >' : identifier was truncated to '255' characters in the debug information c:\program files\microsoft visual studio\vc98\include\vector(60) : warning C4786: 'std::vector<std::basic_string<char,std::char_traits<char>,std::allocator<char> >,std::allocator<std::basic_string<char,std::char_traits<char>,std::allocator<char> > > >::~vector<std::basic_string<char,std::char_traits<char>,std::allocator<char> >,std::allocator<std::basic_string<char,std::char_traits<char>,std::allocator<char> > > >' : identifier was truncated to '255' characters in the debug information c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\camera.h(106) : error C2143: syntax error : missing ';' before '*' c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\camera.h(106) : error C2501: 'GameManager' : missing storage-class or type specifiers c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\camera.h(106) : error C2501: 'gameManager' : missing storage-class or type specifiers GameSceneRender.cpp c:\program files\microsoft visual studio\vc98\include\gl\gl.h(1152) : error C2144: syntax error : missing ';' before type 'void' c:\program files\microsoft visual studio\vc98\include\gl\gl.h(1152) : error C2501: 'WINGDIAPI' : missing storage-class or type specifiers c:\program files\microsoft visual studio\vc98\include\gl\gl.h(1152) : fatal error C1004: unexpected end of file found Keys.cpp c:\documents and settings\max\desktop\angelchronicles\angelchronicles\src\keys.cpp(155) : warning C4800: 'int' : forcing value to bool 'true' or 'false' (performance warning) LoadingRender.cpp c:\program files\microsoft visual studio\vc98\include\gl\gl.h(1152) : error C2144: syntax error : missing ';' before type 'void' c:\program files\microsoft visual studio\vc98\include\gl\gl.h(1152) : error C2501: 'WINGDIAPI' : missing storage-class or type specifiers c:\program files\microsoft visual studio\vc98\include\gl\gl.h(1152) : fatal error C1004: unexpected end of file found MenuRender.cpp c:\program files\microsoft visual studio\vc98\include\gl\gl.h(1152) : error C2144: syntax error : missing ';' before type 'void' c:\program files\microsoft visual studio\vc98\include\gl\gl.h(1152) : error C2501: 'WINGDIAPI' : missing storage-class or type specifiers c:\program files\microsoft visual studio\vc98\include\gl\gl.h(1152) : fatal error C1004: unexpected end of file found Scene.cpp c:\program files\microsoft visual studio\vc98\include\gl\gl.h(1152) : error C2144: syntax error : missing ';' before type 'void' c:\program files\microsoft visual studio\vc98\include\gl\gl.h(1152) : error C2501: 'WINGDIAPI' : missing storage-class or type specifiers c:\program files\microsoft visual studio\vc98\include\gl\gl.h(1152) : fatal error C1004: unexpected end of file found version.cpp Error executing cl.exe. win32.exe - 27 error(s), 5 warning(s)
01-01-2005
Zach L.

Code:

static GameManager *instance(ac_void); // ? ... GameManager *GameManager::instance() { ...

What is 'ac-void' out of curiosity? Is it defined somewhere as void or something else? Anyway, since there aren't errors regarding that, I presume it is.

My guess is that the problem has to do with the following errors:

Quote:

/home/max/programming/c++/gl/angelchronicles/angelchronicles/src/GameManager.h:43: error: ' Scene' is used as a type, but is not defined as a type.
/home/max/programming/c++/gl/angelchronicles/angelchronicles/src/GameManager.h:63: error: parse error before `)' token
/home/max/programming/c++/gl/angelchronicles/angelchronicles/src/GameManager.h:68: error: ISO C++ forbids defining types within return type
/home/max/programming/c++/gl/angelchronicles/angelchronicles/src/GameManager.h:68: error: syntax error before `(' token
compiling GameSceneRender.cpp (g++)
/home/max/programming/c++/gl/angelchronicles/angelchronicles/src/Scene.h:51: error: syntax error before `*' token

Which points strongly toward the problem being with Scene.

*edit*
What also makes me suspicious of that is that you are getting errors on lines 63 and 68 of a 52 line file (unless you didn't post all of GameManager.h).

Cheers,
Zach
01-01-2005
techrolla

Thanks I will look into it. I want to believe that the error is from Camera, a problem with my singleton implementation, but you may be right. If you don't mind, I gave a link above to the snapshot full code archive that has everything. Thanks alot for helping!

Edit: After scanning through Scene, I don't notice anything of worry.

And ac_void is typedef'ed as void.

Oh yea, and the "nonexistent" file line numbers are because I left out the common GPL heading stuff, which is about 15 lines :)
01-02-2005
techrolla

Heres the definition of the error I found online:

Quote:

C2143: syntax error : missing ';' before '*'

If this error is followed by two C2501 errors then the problem is an undeclared class name within a pointer declaration.

For example, the declaration:

CClass *pObject;

will generate the above error message followed by a C2501 error message for 'CClass' and another C2501 message for 'pObject'. The problem is that the compiler isn't recognizing CClass as a valid class/type name. To correct the problem add a #include of the file containing the declaration of CClass (e.g., #include CClass.h)

The problem is, I have the proper header included...
01-02-2005
Da-Nuka

static GameManager *_instance;
UIManager *uimanager;
Scene scene;
Keys keys;

ac_int init(ac_void);
ac_void loopGame(ac_void);
ac_void renderScene(ac_void);

Those functions and such... What happens to them when they arent defined in "public:" nor "private:"?
----------------------------------------------------------------------------
also, i dont know if it help, but have you tried to add
"using namespace std;" in your class-headers?
01-02-2005
Zach L.

Quote:

Those functions and such... What happens to them when they arent defined in "public:" nor "private:"?

They are automatically made private in a class, or public in a struct (so, private in this case).

Nothing appears to be wrong with the singleton implementation itself. And the initialization of _instance is perfectly fine going in the source file.
01-02-2005
techrolla

Hmm...This is really wierd. I guess I will have to look harder at all the files to see if I am missing something somewhere. It fails in both g++ and vc++ 6, so it's not a compiler problem. VC++ 6 says that I don't have the header files included so the type isn't recognized, but I do have the headers. Maybe I will try taking out the singleton, but if you want to take a look at the code, I gave it above in another post. Thanks for your help guys.
01-02-2005
techrolla

Could this be an order of inclusion problem?

It would be greatly appreciated if someone could take a hard look at the code here: http://max.muffinpeddler.com/arch/an...200511.tar.bz2 and tell me if they notice anything whacky. I have such a low morale because of this :o Thanks.

EDIT: Actually, I did get it to compile, but I had to add forward references and make the places of problems into pointers...hmm...I am going to make a new post with new questions, thanks.