>> ... so I see from the archives that Infinity is mandated by ieee754 >> even though my intuition says both should be NaN. > > Other people have other intuitions. It may be that your intuition > is telling you that neither result should be an ordinary number, > and if that's what it's really telling you, it's right: the C > function isfinite(x) is true of all signed zero, subnormal, or > normal x, false of signed infinities and NaNs.
Yeah, on reflection, I think my "intuition" derives from me asking a math teacher back in high school "isn't n/0 infinity?" after looking at a graph, to which he said "no, it's undefined, you can only say it approaches infinity in the limit, but it isn't infinity". >> Every other language throws an exception, even C will crash the >> >> program, > > Not true. C99 *definitely* allows both infinities and NaNs (see > Annex F of the C99 standard) and C89 practice also allowed it. > Some C89 systems required you to use signal() with SIGFPE to > turn IEEE extended results into exceptions; others required you > to use signal() to disable this; others used yet other means. Yes, I was mistaken here, as has been pointed out. And I should definitely know better than to make some generalization about "every other language" among this crowd :) > (Of course, in C what you typically get is garbage, but that can > be put more generally...) Heh, one for the C-bashing quotes file... _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
