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Re: another 754R proposal to vote on



On 2005-05-05 06:02:59 -0600, Nelson H. F. Beebe wrote:
> C99 is a BIG leap forward, but we are now 5 years and 5 months past
> its formal publication, and most Unix systems still lack
> fully-conforming C99 compilers.  On the 20+ flavors of Unix that I
> routinely build and test code on, in over 100 different C and C++
> environments, I know of only three that claim conformance: Intel icc
> on IA-32, IA-64, EM64T, and AMD64, Sun Solaris 10 c99, and
> Hewlett-Packard HP-UX 11 c99).  Recent GNU gcc is close, and even has
> a c99 program, but is in fact not there yet.

Well, it depends on what you mean by "close". The fact that one doesn't
necessarily obtain a double-precision number with gcc on x86 after a
cast to double or an assignment to a double is a very important problem
in some applications. The GCC developers decided that it was a hardware
bug!

Reference: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=323 (and the
various discussions in the duplicates).

The evaluation of floating-point constant expressions is also buggy
(when contracted expressions are disallowed with the FP_CONTRACT
pragma -- which has no effect with gcc).

-- 
Vincent Lefèvre <vincent@xxxxxxxxxx> - Web: <http://www.vinc17.org/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.org/blog/>
Work: CR INRIA - computer arithmetic / SPACES project at LORIA


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