> On Jun 13, 2018, at 9:12 PM, Richard Smith <[email protected]> wrote: > > P0722R3 (wg21.link/p0722r3, just voted into the standard) does not specify a > feature test macro, but I think it would benefit from one. However, it's not > completely clear how we should arrange this: it needs both compiler support > and library support, and is unusable without both. > > Should we add two feature test macros for it (one for compiler, one for > library)? Should we recommend that the library macro be defined only if the > language macro is defined, so that users need only check one, or should we > keep them separate, to allow the library functionality to be discovered > despite the language functionality being absent? (In the latter case, a > library could be built using an old compiler and a new library, and provide > functionality to clients that are built using a new compiler and a new > library.)
I think the normal case is that the compiler and library will be supplied together, so that only the language macro should be needed. In the case where you are using a library from somewhere else, and the library does not include the feature, I think the language feature would need to be disabled in the compiler (e.g., by a command-line option) and that would turn off the language macro. > > Where should such discussions occur these days (now that the feature test > macros have been merged into the standard)? I'm assuming this is still the > right place. I’m not sure, but I think maybe these should start being discussed on the other reflectors. I think we want to continue maintaining sd-6, and things related to that should be discussed here. John. _______________________________________________ Features mailing list [email protected] http://www.open-std.org/mailman/listinfo/features
