What wrong with my code ?

[Lost User]

Hi ALL I wrote some code and i dont know why the compiler throw me this error message : RegistryCall.obj : error LNK2001: unresolved external symbol "private: static class CRegistryCall * CRegistryCall::m_cRegistryCallObject" (?m_cRegistryCallObject@CRegistryCall@@0PAV1@A) RegistryCall.obj : error LNK2001: unresolved external symbol "private: static bool CRegistryCall::m_bExistObject" (?m_bExistObject@CRegistryCall@@0_NA) The code : H file : class CRegistryCall { private: CRegistryCall(); public: static CRegistryCall* CreateInstance(); virtual ~CRegistryCall(); private: static bool m_bExistObject; static CRegistryCall* m_cRegistryCallObject; }; Cpp File : CRegistryCall::CRegistryCall() { m_bExistObject = true; m_cRegistryCallObject = NULL; } CRegistryCall::~CRegistryCall() { if(m_bExistObject) { m_bExistObject = false; delete m_cRegistryCallObject; } } CRegistryCall* CRegistryCall::CreateInstance() { if(!m_bExistObject) { m_bExistObject = true; m_cRegistryCallObject = new CRegistryCall(); } return m_cRegistryCallObject; } This class need to act as singleTon. Thanks for any help.

[_AnsHUMAN_]

Yanshof wrote:

RegistryCall.obj : error LNK2001: unresolved external symbol "private: static bool CRegistryCall::m_bExistObject" (?m_bExistObject@CRegistryCall@@0_NA)

When you use a static variable in a class you need to initialize it with some value in the .cpp file.(or outside the class) SO for the variables that you are using as static (eg for m_bExistObject) put this line on top of the .cpp file. bool CRegistryCall::m_bExistObject =true; and you can do like wise for the other variables too...

Somethings seem HARD to do, until we know how to do them. ;-)_AnShUmAn_

[raghuji rao]

if u writing in a console application then in the project-- settings options, set use mfc in a shared dll option. it will work out

[_AnsHUMAN_]

raghuji.rao wrote:

if u writing in a console application then in the project-- settings options, set use mfc in a shared dll option. it will work out

:doh:

Somethings seem HARD to do, until we know how to do them. ;-)_AnShUmAn_

[Hamid Taebi]

Yes you need to two lines to your code in cpp file bool CRegistryCall::m_bExistObject =true; And also for cRegistryCallObject:)

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WhiteSky

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