On Tue, 26 Jun 2018, Wilco Dijkstra wrote: > > If the library does not set errno, clearly -fno-math-errno by default is > > appropriate (and is the default on Darwin). > > Various librarys no longer set errno nowadays, for example BSD, MUSL, Bionic > etc. For GLIBC 3.0 I'd propose to drop setting of errno as well since very few > applications check errno after math functions that may set it (C89 support > could be added using wrappers that set errno if required).
I think that's clearly something that would require new symbol versions for all affected symbols, or a new SONAME. > That looks incorrect indeed but that's mostly a problem with -fmath-errno as > it > would result in GCC assuming the function is const/pure when in fact it isn't. > Does ATTR_MATHFN_FPROUNDING imply that errno is dead after the call? No, it implies a pure function, so the previous errno value is still live after the call. -- Joseph S. Myers jos...@codesourcery.com
