CODEWITHSUNDEEP
cpointersbit-fields
Vijay
Vijay

Reputation: 73

Accessing bit-field in C by its address

What is the reason behind not allowing to access a bit field in C using its address, is it cause it might not be an address that is not system word aligned ..? or as it doesn't make sense to get bit's address within a byte...?(cause this types pointer arithmetic will be awkward ?)

Upvotes: 2

Views: 8298

Answers (3)

Vicky
Vicky

Reputation: 11

In c smallest addressable unit of memory is considered a Byte. A pointer points to a memory location which can be of any data_type (a pointer is also another variable). Bits receding in byte don't have any address , rather they do have a bit position.

So basically you can not point to particular bit , you can point to a byte or whole word.

Upvotes: 1

Oliver Charlesworth
Oliver Charlesworth

Reputation: 272667

The smallest unit of addressable memory in C is a char, because this corresponds to the smallest unit of addressable memory on most CPU architectures.* It doesn't make sense to talk about the address of a bit.

* One could imagine a hypothetical machine that allowed addressing of individual bits, but it would be pretty esoteric.

Upvotes: 4

David Heffernan
David Heffernan

Reputation: 613332

Bits do not have addresses. That's why you can't refer to them by address. The granularity of addressing is the char.

I guess the reasoning is that the language was design to match the architecture it targeted, and I know of no machine which allows addressing of individual bits.

Upvotes: 7

Related Questions