From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/6118 Path: news.gmane.org!not-for-mail From: Jens Gustedt Newsgroups: gmane.linux.lib.musl.general Subject: Re: [PATCH 1/9] interface additions for the C thread implementation Date: Sun, 07 Sep 2014 16:45:01 +0200 Message-ID: <1410101101.4856.158.camel@eris.loria.fr> References: <20140907002123.GX23797@brightrain.aerifal.cx> <1410081238.4856.137.camel@eris.loria.fr> <1410088603.4856.146.camel@eris.loria.fr> <20140907113220.GB23797@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg="pgp-sha1"; protocol="application/pgp-signature"; boundary="=-ZKMUTpMfVFusHvU7Tbco" X-Trace: ger.gmane.org 1410101110 3824 80.91.229.3 (7 Sep 2014 14:45:10 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sun, 7 Sep 2014 14:45:10 +0000 (UTC) To: musl@lists.openwall.com Original-X-From: musl-return-6131-gllmg-musl=m.gmane.org@lists.openwall.com Sun Sep 07 16:45:05 2014 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1XQdiC-0007zk-LS for gllmg-musl@plane.gmane.org; Sun, 07 Sep 2014 16:45:04 +0200 Original-Received: (qmail 13936 invoked by uid 550); 7 Sep 2014 14:45:03 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 13928 invoked from network); 7 Sep 2014 14:45:03 -0000 X-IronPort-AV: E=Sophos;i="5.04,482,1406584800"; d="scan'";a="93393916" In-Reply-To: <20140907113220.GB23797@brightrain.aerifal.cx> Face: 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 u+rU6wJnprxQf/JvP7beffH5fBIwGIZqEutJUlCKSNoFjYbQiihOkFmih0FJgSUGIpGxstE6RwiLQmsyzcXZesO8N1773YOHKPfUv/uxP726ePjsVNVoT9WZjMq02kRpEKay9+UPXjQmAL1991UuDZ+fGQulSVQrpuqg4pWkkupSjVGshtGZJpzQ9DysfQqZIkgzR7 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 q4emnQ3Df3nxj7z7+t2f+pO/Ysv5U0dm525uKYty3wCetPjRdYNcjaaQabq1Oq1MkVOKkc1reGFhiWIuj7C6JGlKyZNsNor3n7eFStLlkcoKz61fvX/79u3T9cWliTBWvrQEHa0QQmIZgdIK27FQmaKVxIRbN+77z5/4sT/+1PjJEycmosWVmXJvP3YpZM3aNYyuWz 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 xWxyQg9l57BATZZDpuCgH5PMrVxM3G3g513WfNDW3liYRGsPN1ua2LHtq0zM6dOPfmqCDx15227/+ILd58EaNa717/00smp3bsvo7fcS3VpGTcAKV2q1QZJ3MVIC88JsFJN2c+xbrDM+aHPlqE+ji0vY7kWvaFhaaXJzs3nYaoNNq/tJ1/tsiwtnpEOtz/+HHNLMXG 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 1LklihlU2u6NBtNZDaohXHIDKadYWRLsZkZFhgNCaLcB2XzECWalAZhR6v9vzx472v+BF/dxSu3FPf9cY3z0TNLgO+YFNfHzozJHFE4CvW1CPGBvtYabQ5YQuON+aI7YCqUTSX2hgTUeop025IstSiv1wiUQu4fkiz2SBTHaSQ9AQOaZqBk6MTdzFGYAnB0FAvWjD9 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 kELLRU3y0d5Cg1aEZBqSxQJdtprXL5546guXm6QtCwmKOTrvC2NoSq8tw8fYSDx9t8tATVSqNOo16lzdech7Ndrz/a4e/9fqr05+57dCTW7edtz/fE2JIySyHlxqKr8+3OFXooykND8ocf1vwuD1WHO1G5AKPUi5EYVGpLeA4OcqhZtVASKtjkLZFpjM6nZjNG0dnN 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 C3d0WolfKhTp6clRyhcg04xtGCHt1Dh/rExRamYWGyxXa7xn1yYuvkAwP7fClg0Zhx+qr/rM7d+Yesc73nHD5OW7Zh478tRzPxACH/iRa245duzkAdsJfMuy8aXm/FUFlpeWWOm2WZidI9WapaUlFIaTlQ4jfR6/vO9D2NE32LTeYnZOUmnA6PAohx9+qnTy1NnrP/ Cj15cu23XZI4/826Px/xqB37z547sPH374oOvnKTsOb+1zuCoImZARM8ZiLlKkXcWOcoFRJ+Do/CwFO4e2DEe+9Ti+ZXA8ny/cU+X4bMKRZxZIVEiqXI6/+NKuUzPHb7z40ovnX3zx+Ctuq38HyuqWG7Tu+A0AAAAASUVORK5CYII= X-Mailer: Evolution 3.4.4-3 Xref: news.gmane.org gmane.linux.lib.musl.general:6118 Archived-At: --=-ZKMUTpMfVFusHvU7Tbco Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable Am Sonntag, den 07.09.2014, 07:32 -0400 schrieb Rich Felker: > On Sun, Sep 07, 2014 at 01:16:43PM +0200, Jens Gustedt wrote: > > Am Sonntag, den 07.09.2014, 14:05 +0400 schrieb Alexander Monakov: > > > On Sun, 7 Sep 2014, Jens Gustedt wrote: > > > > > > For the C++ API/ABI, these also are different types, now, with = type names > > > > > > (that are used for name mangling, e.g) as listed above. > > > > > >=20 > > > > > > Somebody better versed in C++ could perhaps contribute code tha= t > > > > > > overloads the comparison and assignment operators such that a c= ompilation > > > > > > that tries to compare or copy these types fails. > > > > >=20 > > > > > I'm not sure what you meant by this last paragraph. > > > >=20 > > > > AFAIR in C++ there are ways to inhibit usage of copy assignment by > > > > declaring some "operator=3D" function that is never defined. But my= C++ > > > > has really become rusty. > > >=20 > > > There's no need to do that since those are unrelated structs, and the= refore no > > > operator=3D=3D and operator=3D are available in the first place. You= also can't do > > > that in C (but in C++ you get an error rather than a warning when try= ing > > > to assign pointers). > >=20 > > This is not about assignment between different types and also not for > > pointers but for the struct themselves. > >=20 > > With the current C threads version the following is a priori allowed, > > but shouldn't: > >=20 > > mtx_t a, b; > > mtx_init(&a, mtx_plain); > > b =3D a; > >=20 > > This "works" in C and in C++. > >=20 > > The corresponding code in pthreads would be UB. >=20 > I'm not clear on whether the assignment is well-defined in pthreads, > but actually attempting to use the mutex (by passing it to any of the > pthread_mutex_* functions) would be UB. The same should be true for > C11 threads; if not, it's a defect. It is. > Assignment cannot have predictable > behavior because: >=20 > 1. It could copy a reference (that would later be double-freed if you > destroyed both after the copy) in which case both copies would be a > reference to the same underlying mutex. >=20 > 2. It could contain pointers to its own storage, in which case the > copy would be invalid. >=20 > 3. It could be completely represented by its internal state, in which > case you'd have two potentially working mutexes. >=20 > 4. It could be a reference to some system-level object linked purely > to the address of the mtx_t object, in which case the copy would be > unusable and might even cause system state corruption if used. >=20 > Etc. sure, we all (should) know that, but the average user wouldn't > I don't think the committee intended to forbid any of the above types > of implementation; on the contrary it seems they went out of their way > to support crazy types of implementations, e.g. by omitting > initializers. No, unfortunately for the later, the lack of a definition for default initialization and initializers seems to be intentional. There are people on the committee who defend the interdiction of statically initialized mutexes, seemingly because some oldish windows thread implementation didn't have it. Jens --=20 :: INRIA Nancy Grand Est ::: AlGorille ::: ICube/ICPS ::: :: ::::::::::::::: office Strasbourg : +33 368854536 :: :: :::::::::::::::::::::: gsm France : +33 651400183 :: :: ::::::::::::::: gsm international : +49 15737185122 :: :: http://icube-icps.unistra.fr/index.php/Jens_Gustedt :: --=-ZKMUTpMfVFusHvU7Tbco Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iEYEABECAAYFAlQMb20ACgkQD9PoadrVN+Ke4gCfXgRCCtKeQXdQd1fPWBKs6uy5 TZsAoJWK3dlqyjosVCpts5h4qQVvE0X/ =GJAT -----END PGP SIGNATURE----- --=-ZKMUTpMfVFusHvU7Tbco--