On 02/02/17 14:55, Mason wrote: > On 02/02/2017 14:52, Jonathan Wakely wrote: >> On 2 February 2017 at 13:48, Vincent Lefevre wrote: >>> However, it yields false positives on code that doesn't contain any >>> ambiguity (and is easier to read than lengthier code), such as: >>> >>> #if __STDC_VERSION__ < 199901L >>> >>> Since __STDC_VERSION__ is a standard macro, it is quite obvious that >>> even if __STDC_VERSION__ is not defined, this is not a typo. So, IMHO, >>> -Wundef should whitelist some common macros (and/or perhaps let the >>> user provide his own whitelist). >> >> Yes, it seems reasonable to not warn for __STDC_VERSION__ in C89 mode. >> >> If you spell it wrong it won't match the whitelist and so you'll still >> get a warning. > > Should we open an enhancement request on the bugzilla? > > Regards. > It would probably also make sense to whitelist the other new __STDC__ macros in cases where they are not defined (either because they don't exist in earlier standard modes, or because the implementation chooses not to define them): __STDC_ISO_10646__ __STDC_MB_MIGHT_NEQ_WC__ __STDC_UTF_16__ __STDC_UTF_32__ and also the conditional feature macros (basically, everything in 6.10.8 of the C11 standards that is not otherwise defined). There are probably some C++ predefined macros too.
