--On Tuesday, September 02, 2003 11:35:25 -0400 Bruce Momjian
<pgman@candle.pha.pa.us> wrote:
> Larry Rosenman wrote:
>>
>>
>> --On Tuesday, September 02, 2003 11:20:14 -0400 Bruce Momjian
>> <pgman@candle.pha.pa.us> wrote:
>>
>> > Peter Eisentraut wrote:
>> >> Lee Kindness writes:
>> >>
>> >> > You don't... and you simply shouldn't care. If there is a_r version
>> >> > available then we should use it - even if the plain version is
>> >> > "safe".
>> >>
>> >> The problem with this is that the automatic determination (in
>> >> configure) whether there is a xxx_r() version is, in general,
>> >> fragile. We cannot rely on configure saying that xxx_r() doesn't
>> >> exist, so the plain xxx() should be good enough. Else, we'd be
>> >> shipping claimed-to-be-thread-safe libraries that might trigger bugs
>> >> that will be hard to track down.
>> >>
>> >> I don't see any other solution than keeping a database of NEED_XXX_R
>> >> for each platform and then requiring these functions to show up
>> >> before we declare a library to be thread-safe. So far we're only
>> >> dealing with three functions, to it should be doable.
>> >
>> > Right. We can't assume because a *_r function is missing that the
>> > normal function is thread-safe.
>> So, given that UnixWare doesn't have gethostbyname_r and strerror_r, but
>> does have
>> getpwuid_r, will y'all declare that UnixWare has thread-safety?
>>
>> My vote is YES.
>
> I am inclined to think yes. It would prevent uglification of the code
> by not having to special-case Unixware.
>
> However, I was able to read the libc sources to confirm thread-safety.
> Because you can not see the source, would you try a threaded program and
> see if calls to getpwuid from different threads return different
> pointer values?
It won't prove anything on MY box, as it is a UNIPROCESSOR, so the threads
won't be dispatched at the same time.
It's ok to assume thread-safety, as the SCO developer (Kean Johnston) asked
the threads guys, and he said that the libc stuff is thread-safe so they
don't have to have 2 different versions in libc.
LER
--
Larry Rosenman http://www.lerctr.org/~ler
Phone: +1 972-414-9812 E-Mail: ler@lerctr.org
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