On Wed, 06 Aug 2003 06:00:11 +0200, MJM wrote: > On Monday 04 August 2003 21:40, Sebastian Kapfer wrote: >> > // change the way it is accessed to prove a point int * p_b = (int >> >*) p_a; >> >> Ouch. > > Try this in /usr/src/linux/kernel > > $ grep *\) *.c
This is unfair. First, it's kernel-land code, and second I am not aware of any C++ code in The Kernel. Call me a fundamentalist, but I think such dirty tricks have no gain in modern C++. (There is no alternative in C.) >> > // p_a and p_b point to the same block of dyn. allocated memory; >> >> Do they? > > They do. My app would be broken from the start if I could not rely on > this capability. This style of type conversion is covered in elementary > C++ books by Bjarne. It's not unusual. Exactly where? I don't remember such casts from Bjarne's book. Maybe with a big warning sign next to the code? > You must be aware of what you are doing when you do a type conversion. > Portability is a concern. I am limiting my app to Intel 32 bit Linux. > Screw everything else. Well, if you must... >> Watch out for inheritance, user-defined casting operators and other >> funny stuff. C++ adds a few new meanings to the () casting syntax. In >> general, your assumption is _wrong_. > > I have no user defined casting operators or funny stuff. I'm no fan of > overloading. What about inheritance? Not a fan either? >> One should also note that the C-style casting operator is considered >> bad style in C++. The "politically correct" way to rewrite your example >> is >> >> int *p_b = reinterpret_cast<int *>(p_a); > > By whom? Your example is nowhere to be found in my C++ books by Bjarne. > So you are saying that Bjarne promotes bad style in his books? Why not > tell him: http://www.research.att.com/~bs/homepage.html My "Bjarne" somewhere recommends using the new-style cast operators. I can't provide an actual quote though, since I have the German translation. Maybe you have an older edition of the book; the third or fourth should cover it. BTW, there should be an article about the new casts in the C++ FAQ (I just don't find it at the moment). I'm not going to replicate that stuff here, since it is probably explained in more detail and better English than I can provide. Maybe this can serve as a short intro: http://www.hlrs.de/organization/tsc/services/tools/docu/kcc/UserGuide/chapter_9.html Look in section 9.3, "New-Style Casts". > Besides, reinterpret_cast is probably a template function doing this: > > return ((T) x); // type conversion using cast Erm... no. It is actually an operator built into the language. And it is different from the C-style cast. > That way, you're clearly stating the intent of the cast. It is up to > your >> compiler what it makes of this statement; the C++ standard doesn't >> cover such abuse. > > Language experts sure get their shorts knotted up over simple questions. I'm not a language expert, and I'm not a killer programmer either :-) > I've known some killer programmers and none of them have quoted a > language specification in conversation. We're talking about a corner case here. > That was way over the top. That stuff is for compiler writers, not > application programmers. I did not start a knowledge contest. If I did > inadvertently, then you win. I don't look at it like a contest. There were two contradicting answers, and I wanted to provide proof for mine. Sorry if the language spec was over the top, but what else should I have quoted? I don't think I'll find any C++ expert who debates our specific example of "delete". > I just wanted to discuss a problem with others of similar interest and > try to learn something. I really don't care if my code style is bad, > abusive, or politically incorrect. Well, you now have my opinion on the issue. I won't go after you if you prefer to think differently. Please don't feel offended. -- Best Regards, | Hi! I'm a .signature virus. Copy me into Sebastian | your ~/.signature to help me spread! -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
