From -4023948906532384930 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,ea96cc047f6a22cc X-Google-Attributes: gidf78e5,public X-Google-ArrivalTime: 2001-08-11 05:15:01 PST Path: archiver1.google.com!newsfeed.google.com!newsfeed.stanford.edu!news.tele.dk!small.news.tele.dk!212.74.64.35!colt.net!dispose.news.demon.net!news.demon.co.uk!demon!mail2news.demon.co.uk!not-for-mail From: Francis Glassborow Newsgroups: comp.std.c++ Subject: Re: extern "C" -- what is the intent? Date: Sat, 11 Aug 2001 12:13:57 GMT Organization: Southfield Microcomputer SS Approved: Fergus Henderson , moderator of comp.std.c++ Message-ID: References: <090820010209154805%BobbySchmidt@mac.com> Reply-To: Francis Glassborow X-Trace: mail2news.demon.co.uk 997532043 mail2news:16016 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) MIME-Version: 1.0 X-Newsreader: Turnpike Integrated Version 5.00 U Lines: 37 Xref: archiver1.google.com comp.std.c++:6939 In article , Hans Aberg writes >Well, I don't see in > extern "C" A f(B x) { > // C++ definition > } >if A and B are not C types, how f could be viewed as a C function from the >linking point of view. If they are something else, one must still be able >to convert them to objects that the linker can view as binary C objects >before handing them over to the linker. > >Or so was my impression. If you know how it works, perhaps you should >describe it. extern "C" is about C++. extern "C" void foo(mytype); How does it matter what type mytype is? Unlike function, we do not overload types so as long as mytype has a unique ID, that is the end of the story. Of course a C program cannot pass arguments to foo unless it has a compatible type but that is quite different and not the concern of the linker. The linker only has to find object code from compiling a function definition for foo. If the argument does not match, it is the compilers job to call it out. Francis Glassborow ACCU 64 Southfield Rd Oxford OX4 1PA +44(0)1865 246490 All opinions are mine and do not represent those of any organisation --- [ 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 ]