From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham autolearn_force=no version=3.4.4 X-Google-Thread: a07f3367d7,5edee74b13d8e50a X-Google-Attributes: gida07f3367d7,public,usenet X-Google-NewGroupId: yes X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news1.google.com!news1.google.com!goblin1!goblin3!goblin2!goblin.stu.neva.ru!feeder.erje.net!weretis.net!feeder4.news.weretis.net!news-peer.in.tum.de!news.belwue.de!LF.net!news.enyo.de!not-for-mail From: Florian Weimer Newsgroups: comp.lang.ada Subject: Re: The "black magic" of ioctl Date: Mon, 25 Oct 2010 20:56:03 +0200 Message-ID: <8739ruumnw.fsf@mid.deneb.enyo.de> References: <74b46743-fb81-48cc-a478-ffd069db2fc6@k22g2000yqh.googlegroups.com> <877hh8lkok.fsf@mid.deneb.enyo.de> <87fwvv4gpg.fsf@mid.deneb.enyo.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: idssi.enyo.de 1288032963 28645 172.17.135.6 (25 Oct 2010 18:56:03 GMT) X-Complaints-To: news@enyo.de Cancel-Lock: sha1:T92nC7T8YHkHfE7UvVQcAK+nzXE= Xref: g2news1.google.com comp.lang.ada:14755 Date: 2010-10-25T20:56:03+02:00 List-Id: * Frank J. Lhota: > On 10/24/2010 1:56 PM, Florian Weimer wrote: > >> Perhaps it seems to work for you, but this is not portable. There are >> popular targets where the varargs calling convention is markedly >> different from the non-varargs calling convention, such as amd64. >> It might still work by accident, but all bets are off, really. > > The Microsoft documentation seems to say that varargs is _not_ > markedly different; see > > http://msdn.microsoft.com/en-us/library/dd2wa36c%28v=VS.80%29.aspx There are additional requirements for passing floating-point arguments. It's different from Linux that this will only bite you when you actually pass floating-point arguments which are used in the callee in a certain way (which should happen with ioctl).