cannot call member function without object error

Question

I have a static funcA in ClassA which calls non-static funcB in classA. Although I gave object to the funcB call I still get the error: cannot call member function without object

void* ClassA::funcA(void *arg)
{
   ClassA *pC = reinterpret_cast<ClassA *>(arg);

   funcB(pc);
}

void* ClassA::funcB(ClassA *arg)
{

}

what is the reason for that?

Answer 1

A static class method can be called without an object, like you're doing.
A regular class method needs to be called on an object, like this: objectInstance.classMethod( arguments go here ) or objectPointer->classMethod( arguments go here )

Try this (after changing the signature of funcB in your class declaration to match):

void* ClassA::funcA(void *arg)
{
   ClassA *pC = reinterpret_cast<ClassA *>(arg);

   pC->funcB();
}

void* ClassA::funcB()
{
    ...
}

Answer 2

The problem is that to call funcB it should be done via some object like:

pC->funcB(pC);

Actually this kind of code is more like C than C++ because if you are calling a method on an object you don't need to pass it as a parameter.

Answer 3

You're calling from a static method, so there's no receiver object in the scope.

Consequently, you cannot call a non-static method.

You need an object, which will receive the message: o.funcB(pc);

Answer 4

its not a good idea to call a member function from static function , The reason why it errors out here is that the functionB is invoked from static method . the static method cannot invoke non static member functions . The reason is static function operates on classes not on objects .