Re: Unixware Patch (Was: Re: Beta2 Tag'd and Bundled ...)

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Larry Rosenman <ler(at)lerctr(dot)org>
Cc: Peter Eisentraut <peter_e(at)gmx(dot)net>, Lee Kindness <lkindness(at)csl(dot)co(dot)uk>, "Marc G(dot) Fournier" <scrappy(at)hub(dot)org>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "Marc G(dot) Fournier" <scrappy(at)postgresql(dot)org>, PostgreSQL Development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Unixware Patch (Was: Re: Beta2 Tag'd and Bundled ...)
Date: 2003-09-02 15:35:25
Message-ID: 200309021535.h82FZPP13566@candle.pha.pa.us
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Larry Rosenman wrote:
>
>
> --On Tuesday, September 02, 2003 11:20:14 -0400 Bruce Momjian
> <pgman(at)candle(dot)pha(dot)pa(dot)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?

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073

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