https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53769
--- Comment #22 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> --- (In reply to Florian Weimer from comment #21) > (In reply to Jakub Jelinek from comment #20) > > It is not that easy. __STDC_NO_THREADS__ is a predefined macro, so it would > > mean (at least on targets without stdc-predef.h, with that header one would > > hope that the library describes its implementation correctly) the compiler > > would need on every single compilation try to internally #if > > !__has_include(<threads.h>) #define __STDC_NO_THREADS__ #endif or so. > > I think this would have to be configured at compiler build time. Does this mean that it is not possible to have several C libraries on a system? > Otherwise the macro gets defined if an -I directory happens to contain > a file called threads.h. I suppose that you meant that the macro will *not* be defined by GCC if an -I directory happens to contain a file called threads.h. But having such a directory (with files with the same name as a standard header), isn't this undefined behavior?
