core.stdc.stdatomic

[Richard (Rikki) Andrew Cattermole]

On 15/11/2023 10:55 PM, claptrap wrote:
> That doesnt make any sense, the whole point of CAS is that it is atomic, 
> immediately after it has completed you have no guarantees anyway, what 
> difference does it make if it's wrapped in a function call?

I understand that it seems like it does not make sense. Lock-free 
concurrent data structures are a highly advanced topic, that very few 
people in the world today can implement successfully. About the only 
people who are qualified to touch them for production software would be 
kernel developers for a specific cpu family.

They rely quite heavily on the premise that atomic operations happen 
immediately in the codegen and then based upon the results do set 
actions in response. This is timing based it has to be preciese or they 
will interfere with each other. You do not have much lee-way before you 
start getting segfaults.

I only ever saw partial success with ldc after seven months of 
researching them. For obvious reasons I do not recommend people going 
down this particular path of study, because you are going to get burned 
pretty badly guaranteed.



Regardless compilers like gcc have intrinsics for all of stdatomic. We 
need to be matching it otherwise what D supports will not line up with 
what the system C compiler can offer in terms of use cases. 
https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html