From 5428284351985644509 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,ea96cc047f6a22cc X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2001-08-09 15:49:01 PST Path: archiver1.google.com!newsfeed.google.com!newsfeed.stanford.edu!skynet.be!skynet.be!dispose.news.demon.net!news.demon.co.uk!demon!mail2news.demon.co.uk!not-for-mail From: comeau@panix.com (Greg Comeau) Newsgroups: comp.std.c++ Subject: Re: extern "C" -- what is the intent? Date: Thu, 9 Aug 2001 22:48:13 GMT Organization: Comeau Computing; http://www.comeaucomputing.com Approved: Fergus Henderson , moderator of comp.std.c++ Message-ID: <9kupho$fpp$1@panix3.panix.com> References: <090820010209154805%BobbySchmidt@mac.com> Reply-To: comeau@comeaucomputing.com X-Trace: mail2news.demon.co.uk 997397299 mail2news:1006 mail2news mail2news.demon.co.uk X-Complaints-To: abuse@demon.net X-Mail2News-Path: news.demon.net!mulga.cs.mu.oz.au X-Authentication-Warning: mulga.cs.mu.OZ.AU: fjh set sender to devnull@stump.algebra.com using -f X-Robomod: STUMP, ichudov@algebra.com (Igor Chudov) Lines: 46 Xref: archiver1.google.com comp.std.c++:6911 In article <090820010209154805%BobbySchmidt@mac.com>, Bobby Schmidt wrote: >In my Sep 2001 column for CUJ, I conjecture that the C++ standard's >authors explicitly intend `extern "C"` to let C++ code call C code, but >do not explicitly intend it to allow C code to call C++. The standard >may tolerate C calling C++ -- and indeed, many C++ implementations >allows such calls -- but the standard does not explicitly guarantee or >even endorse this behavior. IMO, it allows both directions, but guarantees neither direction. >Scott Meyers has a different interpretation: `extern "C"` lets code be >called as if it were written in C, regardless of what it's actually >written in. Further, by Scott's reckoning, the standard intentionally >allows such C++ code to be callable from C. (He enshrines this in Item >34 of More Effective C++.) I wouldn't use those words, but otherwise agree with the gist. >To support his argument, Scott draws connections between subclauses 3.5 >and 7.5 that make me a bit nervous. Nonetheless, I'm now thinking that >he's right and my CUJ item is wrong, or at least misleading/incomplete >-- that `extern "C"` is an editorial on the code's apparent semantics, >and not on the actual/intended language of the caller or callee. Unless this says what you just said above, it might be best for you to elaborate upon what you just said. >So I'm appealing for wisdom here: what *exactly* is the Committee's >intent for `extern "C"`? And what of that intent is guaranteed by the >standard vs. simply tolerated? I don't think anything is guaranteed here, but I do think a lot of flexibility and intent is granted. -- Greg Comeau Countdown to "export": December 1, 2001 Comeau C/C++ ONLINE ==> http://www.comeaucomputing.com/tryitout Tasty C99/C++ Combo: Dinkumware libs + Comeau Compilers == WOW!!! --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.research.att.com/~austern/csc/faq.html ]