On Fri, 10 Nov 2017, Bruce Evans wrote: > Hmm, POSIX has the caveat that functions might never see signaling NaNs > since parameter passing might turn them into quiet NaNs (and raise an > exception). I'm used to i387 floating point where this tends to always
So indeed does TS 18661-1 (assignment to the same format and conversion as if by assignment to the same format may be either a convertFormat or a copy operation). For certain functions (fmax / fmin / hypot / pow), however, sNaN arguments (if they reach the function at all) are sometimes handled differently from qNaN arguments + invalid exception, and so you can tell from the result whether the sNaN reached the function (and the TS 18661-1 rule of it being implementation-defined whether that's a domain error, so implementation-defined whether errno should be set in the (math_errhandling & MATH_ERRNO) != 0 case, should still apply). -- Joseph S. Myers jos...@codesourcery.com
