[OpenIndiana-discuss] SS cc multithread compilation switch (e.g., Parrot)

[Udo Grabowski (IMK)]

On 31/10/2012 14:24, James Carlson wrote:
> On 10/31/2012 8:34 AM, Udo Grabowski (IMK) wrote:
>> I don't know where you get your information from, this original
>> documentation says something else:
>> <http://docs.oracle.com/cd/E19205-01/820-7598/bjars/index.html>
>
> PSARC 2001/287 is the source of most of it.  I was an employee of Sun
> from 2000 through 2009, and was chair of the Platform Software
> Architecture Review Committee (PSARC) for much of that time.
>
>> Compiling "successfully" without _REENTRANT does NOT mean that
>> the program actually RUNS flawlessly in a multithreaded environment
>> under all conditions. One source also says that -mt changes dummy
>> locks to real locks, and I don't think you want dummy locks in
>> a mutlithreaded program...
>
> False.
>
> The old dummy-lock crap went away with Solaris 10.  That's the essence
> of this comment in the libpthread man page:
>
>       Historically,  functions  in  this  library  provided  POSIX
>       threading  support. See standards(5). This functionality now
>       resides in libc(3LIB).
>
> It turned out that the dummy locks were *MUCH* harder to maintain (test
> and code around) than the real thing, and the real thing is just as
> cheap in terms of performance.  That's why Roger Faulkner (raf) merged
> it all into libc.
> > ....
>>
>> Or is all this documentation totally outdated and wrong ??
>
> It's outdated.  The Sun Studio folks are a completely separate group
> from the folks who actually built Solaris.  The two groups have little
> technical contact.
>
 > ....

Thanks a lot for this info, it's a pity that this isn't documented
well, I also read the Multithread Guide
<http://docs.oracle.com/cd/E19253-01/816-5137/compile-74765/index.html>
and it's all not entirely complete nor completely consistent...
confusing, at best.
-- 
Dr.Udo Grabowski    Inst.f.Meteorology a.Climate Research IMK-ASF-SAT
www-imk.fzk.de/asf/sat/grabowski/ www.imk-asf.kit.edu/english/sat.php
KIT - Karlsruhe Institute of Technology            http://www.kit.edu
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