sizeof(void*) and sizeof(function_type_ptr*) equality

sizeof(void*) and sizeof(function_type_ptr*) equality

Must sizeof(void*) and sizeof(function_type_ptr*) be equal? Is it required by C (C90, C99) standard?

function_type_ptr is pointer to function.

This question is about standard requirements, not your own opinion. Please, give links, section numbers and quotations from standards

The answer is no.

6.2.6.1/2: Except for bit-fields, objects are composed of contiguous sequences of one or more bytes, the number, order, and encoding of which are either explicitly specified or implementation-defined.

No such specification is done for function / void pointers.

According to this post the answer is no, there is no guarantee that even sizeof(int*) is the same as sizeof(double*).