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

[Scott Long]

Daniel Eischen wrote:
> 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.
> 

I'm in strong agreement here.  David?

Scott