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Re: your patch
- To: mark at codesourcery dot com (Mark Mitchell)
- Subject: Re: your patch
- From: "John David Anglin" <dave at hiauly1 dot hia dot nrc dot ca>
- Date: Wed, 13 Jun 2001 17:28:22 -0400 (EDT)
- Cc: bkoz at redhat dot com, dave dot anglin at nrc dot ca, rittle at labs dot mot dot com, gcc-patches at gcc dot gnu dot org, libstdc++ at gcc dot gnu dot org
> Threads are hairy. Cross-platform threads more so. Unfortunately,
Totally agree. I have spent a lot of time thinking about this over
the past couple of weeks.
> I do not understand this code very well. It looks sane enough to me,
> but we need more eyes.
> We definitely need a review from at least one of, and probably
> both of, Loren and Benjamin. Please look at this very, very carefully
> to convince yourselves that this code is an improvement over what is
> currently there. Try to think about race conditions, etc. If this
> is only to fix HPUX 10, think about whether or not this patch
> is likely to screw up on other more common platforms.
The code only changes the behavior of what is there now for systems
that define __GTHREAD_MUTEX_INIT_FUNCTION or at least that is the
intention. The more common platforms, which have posix threads, define
__GTHREAD_MUTEX_INIT. I have checked very carefully that there is
no screw up for i686 linux, a platform which uses gthr-posix and
For system that define __GTHREAD_MUTEX_INIT_FUNCTION, the current
code does not initialize the _STL_mutex_lock struct and the code
will malfunction the first time that an attempt is made to lock the
mutex _M_lock. It is almost impossible for a user to determine
what needs to be initialized and how to do it.
The integration of GTHREADS into v3 was recently done
and this is a follow up to that patch.
Loren and I have had considerable discussion about race conditions
that can arise on multiprocessor systems. I believe that the issues
have been addressed at least as well as they have been in eh_globals.cc.
J. David Anglin firstname.lastname@example.org
National Research Council of Canada (613) 990-0752 (FAX: 952-6605)