MESSAGE
DATE | 2011-06-11 |
FROM | Ruben Safir
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SUBJECT | Subject: [NYLXS - HANGOUT] (fwd) Re: Using sizeof in the preprocessor
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-- forwarded message -- Path: reader1.panix.com!panix!usenet.stanford.edu!news.glorb.com!border3.nntp.dca.giganews.com!Xl.tags.giganews.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local2.nntp.dca.giganews.com!news.giganews.com.POSTED!not-for-mail NNTP-Posting-Date: Sat, 21 May 2011 08:42:08 -0500 From: Pete Becker Organization: Roundhouse Consulting, Ltd. Newsgroups: comp.lang.c++ Date: Sat, 21 May 2011 09:42:08 -0400 Message-ID: <2011052109420832334-pete-at-versatilecodingcom> References: <4dd7bfa5$0$7624$9b4e6d93-at-newsspool1.arcor-online.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: Using sizeof in the preprocessor User-Agent: Unison/2.1.4 Lines: 24 X-Usenet-Provider: http://www.giganews.com X-Trace: sv3-Fzru1SJoBPw/1jhdSkdE2BDxGAmmBCPE5oRZrFoz00Te/rAYkrarKg8NrPmw/9NdTlIVgrgS2JwDqrD!L0Nq5NhLmA5x0WqY1cBbKEdQSUJ08UUpArN43Jcq2UeLx4jqKK23sW+KG1sgHoVLeup96qQk X-Complaints-To: abuse-at-giganews.com X-DMCA-Notifications: http://www.giganews.com/info/dmca.html X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly X-Postfilter: 1.3.40 X-Original-Bytes: 1856 Xref: panix comp.lang.c++:1085096
On 2011-05-21 09:35:53 -0400, Johannes Schaub said:
> I have this code in my pet project > > #if sizeof -1 > 4 > #error "This doesn't work on 64bit" > #endif > > My friend was telling me that this shouldn't work because "sizeof is not > evaluated in the preprocessor". Yet the compiler accepts it and my program > works. > > Can anybody please explain this? Is it a compiler bug? Thanks to all!
Bug or extension. The preprocessor does text manipulation; it doesn't know anything about types (although it has its own set of rules for arithmetic).
-- Pete Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The Standard C++ Library Extensions: a Tutorial and Reference (www.petebecker.com/tr1book)
-- end of forwarded message --
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