cvs commit: src/sys/kern kern_thr.c syscalls.master src/sys/sys thr.h

[Daniel Eischen]

On Sat, 18 Aug 2007, Robert Watson wrote:

>
> On Sat, 18 Aug 2007, Tijl Coosemans wrote:
>
>> Perhaps it should be stressed in documentation that this syscall is only 
>> meant for Wine and to be removed at some point when better solutions become 
>> available. I want to test this sigqueue solution some more, because the 
>> indirection in signal delivery causes trouble when a thread signals itself. 
>> I guess this would have to be special-cased somehow then.
>
> As a general rule, removing system calls is discouraged as it breaks backward 
> compatibility allowing newer kernels to run older applications, so I think we 
> should avoid adding a system call with the intent to remove it in mind at the 
> time it's added :-).  While thr_kill2() is imperfect from several 
> perspectives, it is certainly a minimalist and logical construction that can 
> be easily understood, and that's pretty valuable.

You can say that about a lot of APIs, but that doesn't mean we should add
them.  This is a bit of a hack to satisfy one application (Wine) when there
are other (perhaps harder) ways to skin the cat.  We certainly don't want
anything else using this API, so I'd advocate removing it.

-- 
DE