# Re: \[PATCH 1/24\] make atomic\_read() behave consistently on alpha

- From: Andi Kleen \<hidden\>
- Date: 2007-08-10 09:08:51 
- List: netdev
- Page: https://ratatoskr.run/netdev/2007/08/991950
- Thread: https://ratatoskr.run/linux-arch/2007/08/991528/t.md

```text
On Friday 10 August 2007 10:21:46 Herbert Xu wrote:
> Paul E. McKenney [ref] wrote:
> >
> > The compiler is within its rights to read a 32-bit quantity 16 bits at
> > at time, even on a 32-bit machine.  I would be glad to help pummel any
> > compiler writer that pulls such a dirty trick, but the C standard really
> > does permit this.
> 
> Code all over the kernel assumes that 32-bit reads/writes
> are atomic so while such a compiler might be legal it certainly
> can't compile Linux.

Yes, the kernel requirements are much stricter than ISO-C. And besides
it is a heavy user of C extensions anyways. On the other hand some of the
C99 extensions are not allowed. And then there is sparse, which enforces
a language which sometimes is quite far from standard C. You could say it is 
written in Linux-C, not ISO C. 

-Andi
```