On 2010-03-17 17:14:37 +0100, Giacomo A. Catenazzi wrote: > From C standard (not really the standard, but the draft n1256: > 5.2.4.2.2, point 5): > > : The accuracy of the floating-point operations (+, -, *, /) and of > : the library functions in <math.h> and <complex.h> that return > : floating-point results is implementationdefined, > : as is the accuracy of the conversion between floating-point > : internal representations and string representations performed by > : the library functions in <stdio.h>, <stdlib.h>, and <wchar.h>. > : The implementation may state that the accuracy is unknown.
The values are defined by 5.2.4.2.2p2 (see the equality). The model is that a floating-point number represents a real number, not an interval. "accuracy" is a measure of the difference between the exact value and the (rounded) value returned by the function. > So maybe the bug is to define __STDC_IEC_559__ on such case. > > OTOH, section F9.1 don't require (my interpretation) > trigonometric to be IEC 60559 functions. It has such requirement > for more elementary functions, e.g. for sqrt (see section F3). Yes, elementary functions are not covered by Annex F (which is on the old IEEE 754-1985 standard). However, a C implementation could claim to conform to IEEE 754 (i.e. more than being conform to ISO C). This is more a quality of implementation. Note: I don't know about other languages, whose implementation could also use the glibc. They could be more restrictive than C. -- Vincent Lefèvre <vinc...@vinc17.net> - Web: <http://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / Arénaire project (LIP, ENS-Lyon) -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org