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Help needed about multiple includes?

Started by Great_White Aug 11, 2007 at 6:51 PM 3 replies 900+ views

Original Post

Aug 11, 2007 at 6:51 PM

I am developing a Framework for use with OpenGL . But I've come across a problem about header files. So far my source files are WinApp.h,WinApp.cpp, GLRenderer.h, GLRenderer.cpp. I packed all common files(windows.h, string.h, etc) into a stdafx.h header. But whenever I try to include it in some files, compiler gives the error LNK1169 (multiple defined symbols)found in XXX.obj. How can I avoid this?

dave

Aug 11, 2007 at 6:53 PM

Can you paste your stdafx.h please.

Alan Kemp

Aug 11, 2007 at 6:56 PM

This is (probably) happening becuase you are defining variables in your header files. The header file then gets included into two seperate cpp files which when compiled each setup a variable with the same name. At linking the names conflict.

Not to get into the whole "global variables are bad thing" (don't worry, several people will be along shortly to beat that horse to death), you should be defining your variables in your cpp files, then declaring them as extern in the header so other cpp files can also use them.

Great_White

Aug 11, 2007 at 7:06 PM

Quote:
Original post by Dave
Can you paste your stdafx.h please.

Here is the stdafx

#pragma once#ifndef _GLSTDAFX_H#define _GLSTDAFX_H// Disable pointer truncation warnings#pragma warning ( disable : 4311 ) #pragma warning ( disable : 4312 )#pragma warning ( disable : 4267 )// Disable str deprecation warnings#define _CRT_SECURE_NO_DEPRECATE// Link OpenGL Libs#pragma	comment(lib, "opengl32.lib")#pragma comment(lib, "glu32.lib")#define WIN32_LEAN_AND_MEAN#include <windows.h>#include <GL/gl.h>#include "../GLext/glext.h"	 // GL Extensions#include "../GLext/wglext.h" // WGL Extensions#include <GL/glu.h>#include <assert.h>#include <string>#include <new>      #include <cmath>#include <ctype.h>#include <fstream>#include <crtdbg.h> // For Debugging#include <stdexcept> // Exceptions// Use 16bit Unicode character strings#include <tchar.h>typedef std::basic_string<TCHAR> w_string;#include <vector>#include <algorithm>// For Performing automatic leak checking at program exit #if defined(ENABLE_MEM_LEAK_CHCK)_CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );#endif// User defined header files//---------------------------------------#include "../Math/MathFuncs.h"// Type declarationstypedef unsigned char		byte;typedef char			ch;typedef float			f32;typedef int			i32;typedef unsigned int		ui32;typedef double			d64;typedef unsigned short		us16;typedef signed short		s16; typedef signed int		si32; #if MSC_VER >= 1300	typedef __int64			i64; #else	typedef __int64			i32;#endif// Some Macros for Safe Pointer Releasing #ifndef SAFE_DELETE#define SAFE_DELETE(p)       { if(p) { delete (p);     (p)=NULL; } }#endif#ifndef SAFE_DELETE_ARRAY#define SAFE_DELETE_ARRAY(p) { if(p) { delete[] (p);   (p)=NULL; } }#endif#endif

JohnBolton

Aug 12, 2007 at 8:37 PM

Perhaps it related to these lines. _CrtSetDbgFlag is a function. What are you trying to do here?

    #if defined(ENABLE_MEM_LEAK_CHCK)    _CrtSetDbgFlag(_CRTDBG_ALLOC_MEM_DF | _CRTDBG_LEAK_CHECK_DF );    #endif

Anyway, whenever you post a question asking why you are getting an error, you must post the error and the source of the error. Obviously, the error tells you which variables are multiply defined. It would make it a hundred times easier for us to figure out the problem if we knew which variables were involved, too.

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