On Tue, 25 Mar 2014, Matthew Fortune wrote: > Can you envisage any way of us raising a warning/error if INVALID > exceptions get enabled in this hybrid NaN world? I believe that is the > only major problem area with mixing NaNs. I.e. It should be possible to > introduce a magic symbol if LD merged opposing NaN modules and have > fesetexcept check for it but I can't think up a way to indicate to > fesetexcept if LDSO linked opposing NaN modules (I'm not sufficiently > experienced with dynamic linkers to know what is possible though).
fesetexcept - a new function in TS 18661-1, not implemented in glibc - has nothing to do with this; the issue is about exceptions from arithmetic rather than those from functions explicitly setting them. And to a first approximation you can ignore exceptions being "enabled" (i.e. traps being enabled) and presume they are tested for by C99 facilities such as fetestexcept - which has no way to return any sort of error status. -- Joseph S. Myers jos...@codesourcery.com
