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Re: Use of Dual Core causes random failures building OpenJDK


On 11/21/09, Christopher Faylor
<cgf-use-the-mailinglist-please@cygwin.com> wrote:
> On Sat, Nov 21, 2009 at 08:16:29AM -0500, mike marchywka wrote:
>>On 11/21/09, Corinna Vinschen wrote:
>>>No, never.  If there is a concurrency problem with the envionment, it's
>>>between threads of the same process.  In that case, we can make getenv,
>>>setenv and friends thread-safe, but it's still actually a problem of
>>>the application, given that getenv, setenv and friends are not
>>>thread-safe per POSIX.  See
>>>http://www.opengroup.org/onlinepubs/9699919799/functions/setenv.html
>>>http://www.opengroup.org/onlinepubs/9699919799/functions/getenv.html
>>>http://www.opengroup.org/onlinepubs/9699919799/functions/unsetenv.html
>>>
>>
>>well, the question was somewhat rhetorical/disingenuous but I don't see
>>how in the general case then the OS can allow two simultaneous
>>processes to modify windoze env variables in a way that corrupts them.
>>The app is responsible for itself but I'm not sure what it can do with
>>respect to other processes.  If you wanted an emulation layer to be
>>safe you are still limited by the OS( but you may have already known
>>that LOL).
>
> I am beginning to think that this is a troll.  Corinna talks about
> threads and you talk about processes.  Either you're clueless about the
> distinction or you are just "having fun".

No, read my posts. I contributed an observation that suggests the
windoze variables don't handle concurrent updates well. Two threads
needn't come from same process. Corinna stated as fact that the MSFT
variable updates
are supposed to be safe, creating some confusion about the accureacy
or usefulness of my observation. Perhaps my memory is not
right or there is some other issue with running multiple installs at once.

In any case, the OP's issue should have been better resolved as it was
determined cygwin isn't required to make this stuff thread safe.

>
> There are simple things that can be done to make Cygwin's handling of
> environment variables thread safe.  Stop arguing about it.  You're just
> looking stupid now.

Well, again, if the OS has some underlying issue there may be nothing you
can do with processes that don't call through cygwin dll. Alternatively, there
may be reasons you don't want some things thread safe etc. So, I'm not
sure what
platitude is at issue here. The thing Corinna sited said they don't
need the setenv
needn't be thread safe, what are the issues etc etc. Plenty you could
argue about,
I just wasn't sure if the OS would let you make a bullet proof solution.



>
> cgf
>
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