4 Mar
2025
4 Mar
'25
6:37 a.m.
Noel Chiappa writes:
The area I'm thinking of (and which I saw a lot
of) is code to implement
network protocols (and I'm fairly astounded that nobody else has mentioned
this yet).
Network packets, tape records, disk images. It's a bit off-topic, so I
have tried to stay silent.
One has to have _absolute_ control over how the bits
are laid out
in the packet (which of course might wind up in any one of countless other
machine types) - which generally means how they are laid out in memory.
The whole concept of C declarations is not rich enough to really deal with
this properly.
I NEVER EVER use C structs or bit fields for this. I get the raw octets
(or whatever the byte size is), and shift and mask accordingly to get
the data fields.