Re: [HACKERS] PostgreSQL libraries - PThread Support, but

Lee, I have been looking at the code, and though the quoted function is
OK to avoid the non-posix case, it seems the later ones are a problem:

#if defined HAVE_NONPOSIX_GETPWUID_R
/* broken (well early POSIX draft) getpwuid_r() which returns
* 'struct passwd *' */
*result = getpwuid_r(uid, resultbuf, buffer, buflen);
#else
/* no getpwuid_r() available, just use getpwuid() */
*result = getpwuid(uid);
#endif /* HAVE_NONPOSIX_GETPWUID_R */
return( (*result == NULL) ? -1 : 0 );

In this case, what logic do we use? Seems you don't want to use
getpwuid_r if it exists, but only if getpwuid isn't thread safe, and I
have no idea how do to this. Can we just use the *_r versions if they
exist?

---------------------------------------------------------------------------

Bruce Momjian wrote:
>
> Lee, I have a question about this code:
>
> char *pqStrerror(int errnum, char *strerrbuf, size_t buflen)
> {
> #if defined HAVE_STRERROR_R
> /* reentrant strerror_r is available */
> strerror_r(errnum, strerrbuf, buflen);
> return strerrbuf;
> #elif defined HAVE_NONPOSIX_STRERROR_R
> /* broken (well early POSIX draft) strerror_r() which returns 'char *' */
> return strerror_r(errnum, strerrbuf, buflen);
> #else
> /* no strerror_r() available, just use strerror */
> return strerror(errnum);
> #endif
> }
>
> Why do we have to care about HAVE_NONPOSIX_STRERROR_R? Can't we just
> use the HAVE_STRERROR_R code in all cases?
>
> ---------------------------------------------------------------------------
>
> Lee Kindness wrote:
> Content-Description: message body text
>
> > Patch attached, along with new libpq-reentrant.c and libpq-reentrant.h
> > files for src/interfaces/libpq.
> >
> > Also at http://services.csl.co.uk/postgresql/
> >
> > Thanks, Lee.
> >
> > Lee Kindness writes:
> > > Ok guys, I propose that the new libpq diff and 2 source files which
> > > i'll soon send to pgsql-patches is applied to the source. This diff is
> > > a cleaned up version of the previous version with the wrapper
> > > functions moved out into their own file and more comments added. Also
> > > the use of crypt_r() has been removed (not worth the effort), the
> > > cpp defines have been renamed to be consistent with each other and
> > > Tom's concerns with loose #defines has been partly addressed.
> > >
> > > This diff does not include any configure changes. I plan to tackle
> > > this separately ASAP, and hopefully produce something more acceptable.
> > >
> > > I will add checks for appropriate compiler thread flags (for compiling
> > > libpq, and alow the removal of #defines in libpq-reentrant.h), and
> > > link flags & libs (for a planned threaded libpq test program and
> > > renentrant ecpg library). If a thread environment is found then check
> > > for the reentrant functions will be done.
> > >
> > > Looking at various open source projects configure.in files there seems
> > > to be little commonality in the thread test macros (telp gratefully
> > > accepted!), I currently think that something like the approach used by
> > > glib is most suitable (switch on OS).
> > >
> > > All sound acceptable?
> > >
> > > Thanks, Lee.
> > >
> > > Peter Eisentraut writes:
> > > > Lee Kindness writes:
> > > >
> > > > > Patches attached to make libpq thread-safe, now uses strerror_r(),
> > > > > gethostbyname_r(), getpwuid_r() and crypt_r() where available. Where
> > > > > strtok() was previously used strchr() is now used.
> > > >
> > > > AC_TRY_RUN tests are prohibited. Also, try to factor out some of these
> > > > huge tests into separate macros and put them into config/c-library.m4.
> > > > And it would be nice if there was some documentation about what was
> > > > checked for. If you just want to check whether gethostbyname_r() has 5 or
> > > > 6 arguments you can do that in half the space.
> >
>
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> --
> 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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--
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