From -4385507959139690477 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: f78e5,dcef0df6016e8f01 X-Google-Attributes: gidf78e5,public From: "James Russell Kuyper Jr." Subject: Re: about #pragma ident Date: 1998/10/05 Message-ID: <361825C1.2275575B@wizard.net>#1/1 X-Deja-AN: 397832598 Content-Transfer-Encoding: 7bit Approved: Fergus Henderson References: <19981003185805.03740.00003431@ng-fb1.aol.com> <6v6ijp$bf3$1@engnews1.eng.sun.com> X-Original-Date: Sun, 04 Oct 1998 21:49:53 -0400 Content-Type: text/plain; charset=us-ascii X-Trace: news6.ispnews.com 907552200 206.161.15.124 (Sun, 04 Oct 1998 21:50:00 EDT) Organization: Not Enough X-Auth: PGPMoose V1.1 PGP comp.std.c++ iQBFAgUANhhzTOEDnX0m9pzZAQFQRgGAkZq7FflQAjiYyoeSGESjDXXQiJH1+14a XKfnvJlZpRFSu50h4Bc5Pzn85GH//wwS =SqEJ Mime-Version: 1.0 NNTP-Posting-Date: Sun, 04 Oct 1998 21:50:00 EDT Newsgroups: comp.std.c++ Steve Clamage wrote: .... > All pragmas are entirely implementation-defined, according > to the C++ standard (and the C standard as well). By definition, > there is no standard use or behavior for any pragma, except > that compilers are required to ignore unrecognized pragmas. You're right about C++, and about the current C standard. However, the following #pragma's have a standard-defined meaning in the draft C9X standard: #pragma STDC FP_CONTRACT on-off-switch #pragma STDC FENV_ACCESS on-off-switch #pragma STDC CX_LIMITED_RANGE on-off-switch Where on-off-switch is either OFF or ON. No other #pragmas starting with "STDC" will be legal in C9X (and therefore, a strictly conforming program can't be sensitive to whether or not they are supported by the implementation). FP_CONTRACT determines whether floating point operations are permitted to be contracted, so as to avoid the rounding errors implied by the actually written operations. FENV_ACCESS indicates whether the code will need access to the floating point environment test/set functions. CX_LIMITED_RANGE allows the compiler to use the faster simplified formulas for such things as complex muliply, divide, and absolute value, that only work correctly for a limited (but large) range of values. --- [ 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://reality.sgi.com/austern_mti/std-c++/faq.html ]