Function Pointer from base class
i need a Function Pointer from a base class. Here is the code:
class CActionObjectBase
{
...
void AddResultStateErrorMessage( const char* pcMessage , ULONG iResultStateCode);
...
}
CActionObjectCalibration( ): CActionObjectBase()
{
...
m_Calibration = new CCalibration(&CActionObjectBase::AddResultStateErrorMessage);
}
class CCalibration
{
...
CCalibration(void (CActionObjectBase::* AddErrorMessage)(const char*, ULONG ));
...
void (CActionObjectBase::* m_AddErrorMessage)(const char*, ULONG );
}
Inside CCalibration in a Function occurs the Error. I try to call the Function Pointer like this:
开发者_如何学Pythonif(m_AddErrorMessage)
{
...
m_AddErrorMessage("bla bla", RSC_FILE_ERROR);
}
The Problem is, that I cannot compile. The Error Message says something like: error C2064: Expression is no Function, that takes two Arguments.
What is wrong?
regards camelord
You need to provide an object on which you call the member function:
CActionObjectBase* pActionObjectBase /* = get pointer from somewhere */ ;
(pActionObjectBase->*m_AddErrorMessage)("bla bla", RSC_FILE_ERROR);
Unlike normal object and function pointers, pointers to members can only be deferenced using an object of the appropriate type via the .*
(for objects and references) or ->*
(for pointers to objects) operators.
You need to invoke m_AddErrorMessage
on an object, something like:
(something->*m_AddErrorMessage)(...)
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