No it may not.
According to the C Standard (6.3.2.3 Pointers)
1 A pointer to void may be converted to or from a pointer to any
object type. A pointer to any object type may be converted to a pointer to void and back again; the result shall compare equal to
the original pointer.
As for function pointers then
8 A pointer to a function of one type may be converted to a pointer to
a function of another type and back again; the result shall compare
equal to the original pointer. If a converted pointer is used to call
a function whose type is not compatible with the referenced type, the
behavior is undefined.
In the C++ Standard there is more detailed definition of pointers (3.9.2 Compound types)
3 The type of a pointer to void or a pointer to an object type is
called an object pointer type....The type of a pointer that can
designate a function is called a function pointer type.
And
4 A pointer to cv-qualified (3.9.3) or cv-unqualified void can be used
to point to objects of unknown type. Such a pointer shall be able to
hold any object pointer. An object of type cv void* shall have the
same representation and alignment requirements as cv char*.
