Date: Wed, 21 Apr 2004 01:22:18 -0400 From: Joe Marcus Clarke <marcus@FreeBSD.org> To: Daniel Eischen <eischen@vigrid.com> Cc: freebsd-hackers@FreeBSD.org Subject: Re: Help: threading problem in non-threaded applications Message-ID: <1082524938.41182.26.camel@shumai.marcuscom.com> In-Reply-To: <Pine.GSO.4.10.10404201652240.14017-100000@pcnet5.pcnet.com> References: <Pine.GSO.4.10.10404201652240.14017-100000@pcnet5.pcnet.com>
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--=-akjjKJEg+CZ8tCZxwMlk Content-Type: text/plain Content-Transfer-Encoding: quoted-printable On Tue, 2004-04-20 at 17:08, Daniel Eischen wrote: > On Tue, 20 Apr 2004, Joe Marcus Clarke wrote: >=20 > > I have a problem I'm hoping someone can help me with. GTK+ 2.4 > > introduced a new file selection GUI which works just fine in threaded > > and non-threaded applications. However, GNOME 2.6 augmented this dialo= g > > with a dynamically loadable threaded shared object. The GNOME version > > is automatically used by all GTK+ apps when run under a GNOME desktop i= f > > libgnomeui is installed. >=20 > Shared libraries shouldn't link with threading libraries > unless they actually create threads behind the scenes. > Actually, even so, they could force the (unthreaded) > applications that link with them to explicitly supply > the thread library in the link option. And that's the case here. The underlying libraries are creating and using threads. But what happens when a non-threaded application loads a thread library via dlopen() (which is the case here)? Here's the stack trace I see: #1 0x28b474b5 in _spinlock_debug () from /usr/lib/libc_r.so.5 No symbol table info available. #2 0x28b4c873 in _mutex_cv_lock () from /usr/lib/libc_r.so.5 No symbol table info available. #3 0x28b4c738 in _mutex_cv_unlock () from /usr/lib/libc_r.so.5 No symbol table info available. #4 0x28b50e50 in _pthread_cond_wait () from /usr/lib/libc_r.so.5 No symbol table info available. #5 0x28b50fa0 in pthread_cond_wait () from /usr/lib/libc_r.so.5 No symbol table info available. #6 0x288af4e3 in pthread_cond_wait () from /lib/libc.so.5 No symbol table info available. #7 0x28a00262 in giop_recv_buffer_get (ent=3D0xbfbfd9d0) at giop-recv-buffer.c:707 tdata =3D (GIOPThread *) 0x8090320 ... Under normal circumstances, this application doesn't need to be linked to PTHREAD_LIBS. However, for this one option (--file-selection in this case), a threaded module is dlopen()'d, and this happens. [snip] > Try using -pthread to build the shared library instead of > -lpthread. That will avoid the link to libpthread. If > it's only locking that the library needs, libc should have > all the necessary stubs. It's more than just locking. Threads are being created. If I go with -pthread, I'd have to relink every GNOME application, and I'm trying to avoid that if possible. Joe >=20 > An alternative is to get GNOME maintainers to use a thread > stub library and have their shared libraries link to that. > The stub library would provide weak locking symbols and > be overridden by applications bringing in real thread > libraries. Perhaps something like that could work. --=20 Joe Marcus Clarke FreeBSD GNOME Team :: gnome@FreeBSD.org FreeNode / #freebsd-gnome http://www.FreeBSD.org/gnome --=-akjjKJEg+CZ8tCZxwMlk Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQBAhgUJb2iPiv4Uz4cRAnlEAJ44ASsdlSyM3YMHH0P7jM8wU2a5EgCbBbaX hX4yziGiOc1Po7xKaSi1syE= =Pnq2 -----END PGP SIGNATURE----- --=-akjjKJEg+CZ8tCZxwMlk--
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