c++ - Address operator with pointer to member function -

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we know create "common" pointer function can example:

void fun(); void (*ptr)() = fun;

the name of function address function start. not need use address operator & this:

void (*ptr)() = &fun;

now pointer member function on contrary must use address operator. example class pointer member function ptr , function fun() must write:

void(a::*ptr)() = &a::fun;

why difference?

it because function defined inside class. pointer member function holds "relative address" of function in class layout , have access way.

in case of static, has no pointer , behaves global function , so, can access normal function pointer.


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