------- Comment #6 from pcarlini at suse dot de 2006-08-07 17:24 ------- (In reply to comment #5) > Insofar as I understand this issue, it seems that C99 and the C++ standard > specify different results for the square root of (-1, -0). > > If that is correct, then we can decide that we want libstdc++ to follow C99 > rather than the C++ standard, but I don't think we can settle that simply by > looking at C99.
Well, I see where the C++ standard says, in 26.2.8/13, "..., the value returned lies on the positive imaginary axis", however, let's admit that the current C++ standard is *very* sloppy about these mathematical subtleties: for one, the *entire* C++ standard has *no* notion of signed zero (at issue here!), neither of NaNs, or infinity, for that matter. Also, more generally, when we decided to use builtins everywhere, thus, eventually, libc functions, we made the choice that consistency with the C library is a must, I don't think we want to change that decision. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28406
