Path: csiph.com!x330-a1.tempe.blueboxinc.net!newsfeed.hal-mli.net!feeder1.hal-mli.net!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 09:37:00 -0500 From: Pete Becker Organization: Roundhouse Consulting, Ltd. Newsgroups: comp.lang.c++ Date: Sat, 21 May 2011 10:37:00 -0400 Message-ID: <2011052110370061214-pete@versatilecodingcom> References: <4dd7bfa5$0$7624$9b4e6d93@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-fErqju4cpSO7xnm/f4yxTUXamk1w0o9tkzaCrkRkQtr5ZHmWvaomac55L/rNra+FlblzFgpR7ETQKD7!MxQPEzsBqs4/aBvcFqU7jX1qp7dh24GJOoIriGN5+iCnF+vfU9nGxfvrcUGX7Yt6JXaMJozv X-Complaints-To: abuse@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: 1749 Xref: x330-a1.tempe.blueboxinc.net comp.lang.c++:5271 On 2011-05-21 10:08:58 -0400, Huibert Bol said: > Johannes Schaub wrote: > >> 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. > > Identifiers in #if expressions are evaluated as zero, Good point. -- Pete Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The Standard C++ Library Extensions: a Tutorial and Reference (www.petebecker.com/tr1book)