[jakub@redhat.com:Linking against libpthread via -pthread?

[Alexander Kabaev]

On Fri, 10 Feb 2006 13:52:04 -0600
Dan Nelson <dnelson at allantgroup.com> wrote:

> In the last episode (Feb 10), Steve Kargl said:
> > On Fri, Feb 10, 2006 at 01:39:08PM -0600, Dan Nelson wrote:
> > > In the last episode (Feb 10), Steve Kargl said:
> > > > Some background information:  I routinely build GCC mainline on
> > > > i386-*-freebsd and amd64-*-freebsd.  GCC mainline is introducing
> > > > OpenMP support.  When libgomp.so.1 is built, the compiler is
> > > > given the -pthread option throughout the construction of
> > > > libgomp.so.1. However, a "ldd libgomp.so.1" shows no dependence
> > > > on libpthread.so.2
> > > 
> > > There was a discussion about this back when the default switched
> > > from libc_r to libpthread, and I think the consensus was that
> > > shared libraries should never record dependencies against threads
> > > libs, which means you have to add -pthread to the link line when
> > > building the final executable.  This avoids problems where an
> > > executable links to three shlibs, one library is linked to libc_r,
> > > one's linked to libkse, and a third is linked to libpthread.
> > 
> > Does this still apply with the symbol versioning that was committed
> > some weeks (months?) ago?  Additionally, I thought libc_r is
> > deprecated in FreeBSD-current (has it been moved to the attic?).
> 
> I think symbol versioning only helps if you want to provide multiple
> compat wrappers for a single symbol depending on the age of the
> calling program.  It won't help two libraries that both want to
> provide the same public symbols but have different internal ABIs
> cooperate.
> 
> libc_r is still the only threads library that provides reliable %CPU
> stats and readable ktrace/truss/strace output afaik.
> 
> -- 
> 	Dan Nelson
> 	dnelson at allantgroup.com
> _______________________________________________
> freebsd-current at freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-current
> To unsubscribe, send any mail to
> "freebsd-current-unsubscribe at freebsd.org"
No. The change to link in libc by default and libpthread with -pthread
are inthe works and will be committed shortly. There is not way around
this if we want working versioned libc and libpthread in our system.

-- 
Alexander Kabaev
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 187 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/freebsd-current/attachments/20060210/43506d04/signature.bin