Re: [BUGS] 8.0.0beta1: -lpthread missing - Mailing list pgsql-patches

From Martin Münstermann
Subject Re: [BUGS] 8.0.0beta1: -lpthread missing
Date
Msg-id 411CA643.8050900@betrusted.com
Whole thread Raw
In response to Re: [BUGS] 8.0.0beta1: -lpthread missing  (Martin Münstermann <mmuenstermann@betrusted.com>)
Responses Missing Manuals  ("Simon@2ndquadrant.com" <simon@2ndquadrant.com>)
List pgsql-patches
Hi!

Martin Münstermann wrote:
>> OK, we now have thread compile failure reports on Debian and Slackware.
>>
>> The config/acx_pthread.m4 script basically tests these:
>>
>>     acx_pthread_flags=3D"pthreads none -Kthread -kthread lthread -pthread
>>         -pthreads -mthreads pthread --thread-safe -mt pthread-config"
>> =09
>> in that order and exits once it finds the first one that can
>> compile/link this:
>>
>>         AC_TRY_LINK([#include <pthread.h>],
>>                     [pthread_t th; pthread_join(th, 0);
>>                      pthread_attr_init(0); pthread_cleanup_push(0, 0);
>>                      pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
>>                     [acx_pthread_ok=3Dyes])
>>
>> Now, the big question is why -pthread can compile/link this successfully
>> but -pthread isn't enough to build a library that uses threads.
>
>
> I suspect that on Solaris, without "-lpthread" the pthread-stubs in
> /usr/lib/libc.so might be called at runtime instead of the functional
> ones in libpthread.so.
>
> Could this easily be checked?

I can confirm this suspect for Solaris8/gcc 3.2.3.
How to reproduce it:
Add a line like
      printf("### NOTE: check_sigpipe_handler called.\n");
to check_sigpipe_handler() in fe-secure.c and rebuild libpq.so.

The line is only dumped out (indicating that check_sigpipe_handler() is
being called), when the library is linked with -lpthread.
Without -lpthread no complains from the compiler or linker, but
check_sigpipe_handler() is not called, because the stub of
pthread_once() in libc.so does nothing.

--> We need -lpthread on solaris, too.

Regards,
  Martin

pgsql-patches by date:

Previous
From: Martin Münstermann
Date:
Subject: Re: [BUGS] 8.0.0beta1: -lpthread missing
Next
From: Andreas Pflug
Date:
Subject: Compiling libpq with VC6