Mail Archives: cygwin/2009/11/20/14:05:17
On 11/20/09, Christopher Faylor
<cgf-use-the-mailinglist-please AT cygwin DOT com> wrote:
> On Fri, Nov 20, 2009 at 01:19:57PM -0500, mike marchywka wrote:
>>On 11/20/09, Corinna Vinschen wrote:
>>> On Nov 20 09:32, Christopher Faylor wrote:
>>>> On Fri, Nov 20, 2009 at 12:20:52PM +0100, Corinna Vinschen wrote:
>>>> >On Nov 20 06:04, mike marchywka wrote:
>>>> >> On 11/19/09, Larry Hall (Cygwin) <reply-to-list-only-lh AT cygwin DOT com>
>>>> >> wrote:
>>>> >>>Wow! I had a hunch that BLODA could be the cause of the file related
>>>> >>>problems but it never occurred to me that it could be screwing up
>>>> >>>environment variables too.
>>>> >>
>>>> >>Anyone care to determine if env updates are not thread safe?
>>>> >
>>>> >It's indeed not thread safe. Looks like we need some locking...
>>>>
>>>> What's "it" in this case? putenv?
>>>
>>> "it" is primarily _addenv, which is used by setenv and putenv.
>>>
>>>> The putenv() function is not required to be reentrant, and the one in
>>>> libc4, libc5 and glibc 2.0 is not, but the glibc 2.1 version is
>>>
>>> Same for setenv and unsetenv, which don't need to be thread-safe per
>>> POSIX. glibc's setenv is thread-safe, though.
>>>
>>>> I agree that it would be nice to make it safer but is there really code
>>>> here which is updating the environment in separate threads?
>>>
>>> And given POSIX, if so, it would be an application bug if the application
>>> doesn't care by itself to use setenv/getenv in a thread-safe manner.
>>
>>Why does the OS let this happen? I thought windoze should avoid
>>garbage.
>
> Er, I think you're a little confused about what we're talking about. The
> OS doesn't enforce thread safety. There's really no way that it can.
We are talking about windoze env variables right? I did ask previously
I thought.
The OS is the only place you can when the threads are in different
processes unknown to each other. Or, can two different processes share
the
same thread? I guess my point is that there is nothing cygwin can do if
windoze doesn't do it. But, that was why I asked what the OP was actually
complaining about. In may case, IIRC, I got garbage in the windoze variables
rather than just some from process A and some from process B.
>
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