somewhat covered in different hacker news post, for C, roughly:

   []

   *()++

Technically, can only do address "1" with first bit set as a valid, usable address on hardware allowing addressing smaller than 8 bits (standard hardware epsilon factor).

So really, address one is literally address 0 + epsilon, where epsilon is minimal addressable bit group, typically 8 bit clean without seg fault.

Although, for standard x86, epsilon size would depend on which ring/boot method level & asm addressing method available (8,16,32,64).