From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: 103376,7b65fc33a05f24b6 X-Google-Attributes: gid103376,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news2.google.com!newshub.sdsu.edu!flph200.ffdc.sbc.com!prodigy.net!flph199.ffdc.sbc.com!prodigy.com!flpi107.ffdc.sbc.com!nlpi068.nbdc.sbc.com.POSTED!cfe18fef!not-for-mail From: Gary Scott Organization: Home User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.7.2) Gecko/20040804 Netscape/7.2 (ax) X-Accept-Language: en-us, en MIME-Version: 1.0 Newsgroups: comp.lang.ada Subject: Re: A curiosity... References: <84d_k.82$Xt.59@newsfe13.iad> In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Message-ID: NNTP-Posting-Host: 68.94.13.153 X-Complaints-To: abuse@prodigy.net X-Trace: nlpi068.nbdc.sbc.com 1228605345 ST000 68.94.13.153 (Sat, 06 Dec 2008 18:15:45 EST) NNTP-Posting-Date: Sat, 06 Dec 2008 18:15:45 EST X-UserInfo1: Q[RGW]CEGJPKR_DYABNLNFXBWR\HPCTL@XT^OBPLAH[\RYIBK^RAQFW[ML\THRCKV^GGZKJMGV^^_JSCFFUA_QXFGVSCYRPILH]TRVKC^LSN@DX_HCAFX__@J\DAJBVMY\ZWZCZLPA^MVH_P@\\EOMW\YSXHG__IJQY_@M[A[[AXQ_XDSTAR]\PG]NVAQUVM Date: Sat, 06 Dec 2008 17:15:35 -0600 Xref: g2news1.google.com comp.lang.ada:2911 Date: 2008-12-06T17:15:35-06:00 List-Id: Hyman Rosen wrote: > Adam Beneschan wrote: > >> This thread started with a comment about a tutorial that showed >> students the "right" way to accomplish a certain task. What do you >> want to bet that this tutorial didn't say "This works only for such- >> and-such implementations" > > > The distinction between right and wrong that the tutorial > was making was about not having multiple threads access a > shared object because of unpredictable timing. I doubt that > there has ever been a C implementation on any architecture > where it was wrong to convert a small integer to pointer > and back. Interesting, I never realized that there is this huge issue or controversy with shared memory/objects. These techniques have been used for 50 years and there are well known ways to synchronize and/or structure data to avoid timing issues. Of course some operating systems are better than others. My experience is mostly with OS' that provide no assistance at all, so you may define a handshaking process into the data access process. -- Gary Scott mailto:garylscott@sbcglobal dot net Fortran Library: http://www.fortranlib.com Support the Original G95 Project: http://www.g95.org -OR- Support the GNU GFortran Project: http://gcc.gnu.org/fortran/index.html If you want to do the impossible, don't hire an expert because he knows it can't be done. -- Henry Ford