Date: Sun, 14 Nov 2004 16:07:46 -0800 From: Sean McNeil <sean@mcneil.com> To: Daniel Eischen <deischen@freebsd.org> Cc: current@freebsd.org Subject: Re: missing weak symbol for pthread_equal in libc Message-ID: <1100477266.89074.15.camel@server.mcneil.com> In-Reply-To: <Pine.GSO.4.43.0411141834220.16228-100000@sea.ntplx.net> References: <Pine.GSO.4.43.0411141834220.16228-100000@sea.ntplx.net>
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--=-aZWYRMzwF80bujqZbo62 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Sun, 2004-11-14 at 18:46 -0500, Daniel Eischen wrote: > On Sun, 14 Nov 2004, Sean McNeil wrote: >=20 > > > > I think pthread_equal should be added to libc. I found it is used in > > libxml2 and a link to that library fails without -pthread. >=20 > The pthread_foo() in libc are mainly for libc usage. If applications > want to use pthread_foo(), they really should be linking to the (a) > threads library. Look at it this way -- if we didn't use any pthread > functions in libc, there wouldn't be _any_ pthread stubs in libc. > Also, we could have used __libc_lock(), __libc_unlock(), etc, in > libc and have the threads libraries override those functions instead > of using _pthread_*(). >=20 > pthread_equal() would be kinda harmless in libc, but you get my > point above, no? After some thought, I agree as pthread_equal is not used within libc, but this brings up the question as to why there are any pthread_* symbols in libc. This is kind of a sore point for me. I actually believe that there should be no weak symbols of pthread_* in libc. A program that uses pthread_cond_init, for example, should not compile without the pthread library. weak symbols to the _pthread_* functions are fine as they are required to provide thread-safe functionality within libs. IMHO, it should be setup as follows: 1) libpthread.so has routines _pthread_* and references as pthread_* (I think they should be strong, but others think weak ;-) - suppose to be funny, not offensive). 2) libc.so accesses those (_pthread_*) functions and has weak symbols for the ones it use to work without libpthread. --=-aZWYRMzwF80bujqZbo62 Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) iD8DBQBBl/NSyQsGN30uGE4RAvChAJ9qyFQR3hMbn8UZFv9btR6Eed6hfQCePV5E fo9SY4UFwYVjoh8evRVlhPA= =h5VB -----END PGP SIGNATURE----- --=-aZWYRMzwF80bujqZbo62--
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