Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com Date: Fri, 28 May 2004 10:54:37 -0500 From: Brian Ford Reply-To: cygwin AT cygwin DOT com To: mathias DOT wagner AT philips DOT com cc: cygwin AT cygwin DOT com Subject: Re: GCC 3.3.1 problem with printf %Lg %Lg and -m128bit-long-double compile option In-Reply-To: Message-ID: References: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-IsSubscribed: yes On Fri, 28 May 2004, mathias.wagner wrote: > To: "Gerrit @ cygwin" http://www.cygwin.com/acronyms/#PCYMTNQREAIYR > Meanwhile I have had some help from another colleague here at Philips and > he found out that the -m96bit-long-double compile option works fine. My understanding is that this is the default ie. no switch requried. > Note that 96 bit is what a long double takes. This makes sense in > conjunction with what Brian said: The alignment of the parameters handed > over to a function is changed when using -m128bit-long-double, and hence > all functions affected must be recompiled - so presumably cygwin itself. Yes. > There was no particular reason for using -m128bit-long-double other than > that I have always used it, and I will switch to -m96bit-long-double. It might have performed better with respect to caching, but YMMV. > But perhaps one could insert somewhere in gcc a warning when using such > a combination of compile options. I know it is in the documentation > somewhere, but compiler warnings are much more visible... :-) You could take this up on the gcc list if it is still important to you, but I suspect they would frown on the idea. The philosophy goes something like this: You had to read the documentation to discover that this switch existed. It is not a compiler warnings job to advise you to read the documentation more carefully. It would also penalize those that did read the docs, so they would want a way to turn off the gratuitous warning with via another switch or attribute. Can you see why this isn't a good idea? -- Brian Ford Senior Realtime Software Engineer VITAL - Visual Simulation Systems FlightSafety International the best safety device in any aircraft is a well-trained pilot... -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/