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Date: | Wed, 16 Sep 2009 11:31:38 +0100 |
From: | Dave Korn <dave DOT korn DOT cygwin AT googlemail DOT com> |
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Subject: | Re: Cygwin 1.7/1.5 C99 conformance (GCC, libc) |
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Matthias Andree wrote: > Now, Cygwin 1.5 and 1.7 appear to lack long double library support in > libc/libm -- which is required for a hosted C99 implementation however, > but not for a freestanding C99 implementation. > > Trying to solve this, I found another Cygwin issue: GCC 3.4.4 sets > __STDC_HOSTED__ to 1 by default (that's a GCC factory default). Just FTR, Cygwin-1.5 and gcc-3.4.4 are end-of-life and will never be updated again. > I propose that this gets overridden to 0 in Cygwin-ported GCC compilers > until the library support for a C99-conforming full hosted > implementation is in place, so that applications can safely check Sorry, I don't think that's a good idea. There are a whole world of other differences implied by the freestanding-vs-hosted distinction that I think it would not be wise for the compiler to lie about. It is indeed unfortunate that our C library support (which derives from newlib) is incomplete, and this gap between theory and practice is what autoconf was invented to bridge. (Autoconf is of course a compromise born of necessity which in an ideal world wouldn't exist. But at least it means these problems can be dealt with in a practical and systematic fashion.) It mightn't be too hard to get long double support into newlib, but it's all a matter of someone having the time and wherewithal to actually do it. cheers, DaveK -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
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