From: "John M. Aldrich" Newsgroups: comp.os.msdos.djgpp Subject: Re: expression evaluation guarantees Date: Sat, 09 Aug 1997 17:08:01 +0000 Organization: Two pounds of chaos and a pinch of salt Lines: 90 Message-ID: <33ECA3F1.7C16@cs.com> References: <97Aug9.163401gmt+0100 DOT 17058 AT internet01 DOT amc DOT de> Reply-To: fighteer AT cs DOT com NNTP-Posting-Host: ppp101.cs.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Precedence: bulk Chris Croughton wrote: > > expected - whether that's because of compiler bugs or (more likely) > coding errors is irrelevant, if you don't test it (in the example > with the "format_hard_drive()" routine just doing a printf) first > then you deserve anything that happens. Including being fired from > your job... Even if the compiler does it right, what if there's an error in the get_user_response() function that causes it to return TRUE in inappropriate circumstances? Whoops! There goes your hard drive! > Certainly there are compilers with bugs in them, but that is not > a valid reason to ignore half the language just in case your > compiler is buggy in that area. Absolutely true. DJGPP is one of the better compilers for this, because (as said over and over), if there really is a bug, you can go fix it yourself! > > P.S.: The first person to actually start that thread again because > > I mentioned it will be slapped with a wet trout. > > That thread appears not to have been on this newsgroup. It seems > that comp.os.msdos.djgpp was about the only one it wasn't posted > to. So I'll take you up on that offer of a fresh trout, and start > it here. What's wrong with exceeding the speed of light? Have you > ever tried it? If not, don't knock it... **SLAP** ;) [NOTE: This is off-topic for the newsgroup, and this will be my last post about it. I encourage all those who are uninterested to skip the remainder of this article, and those who are to continue the conversation via private email. Thanks.] There's nothing wrong whatsoever with _exceeding_ the speed of light; you simply have to define a new set of universal laws. The problem comes in that infinitesimal interval between going slower than light and going faster. As far as we know, it is not possible to cross that barrier. It's an asymptotic equation; the thrust required to accelerate grows to infinity as velocity approaches 'c'. In any case, the whole notion of the speed of light presumes that one is an outside observer watching the moving body in question. From the standpoint of the body itself, it would appear to be motionless while the universe flashed by around it. I don't feel myself moving right now, even though I'm travelling at a certain velocity with respect to the center of the planet (rotation), a different velocity with respect to the Sun, and still another velocity with respect to the center of the galaxy. If I walk forwards (acceleration in one direction), it requires the same amount of effort as walking backwards (acceleration in the opposite direction). From the point of view of any given observer, no other body may appear to travel faster than the speed of light. This is why it's called "relativity." Here's a math question. You are floating in space, "motionless." Two spaceships are approaching you from opposite directions, each travelling at 0.9c (nine tenths of the speed of light). How fast are they approaching each other, from their perspectives? A. 1.8c B. 0.99c A. implies that the photons being emitted by each ship are travelling faster than light with respect to each other. This is impossible, because at some point (when the bodies were accelerating), they would have had to cross the speed of light. B. is the correct answer; each ship observes the other to be approaching at 0.99c, while each observes you to be approaching at 0.9c. To the occupants of each ship, they are "motionless" and the others are moving towards them. -- --------------------------------------------------------------------- | John M. Aldrich | "A committee is a life form with six | | aka Fighteer I | or more legs and no brain." | | mailto:fighteer AT cs DOT com | | | http://www.cs.com/fighteer | - Lazarus Long | ---------------------------------------------------------------------