On 2017-Jun-29, at 5:54 AM, Konstantin Belousov <kostikbel at gmail.com> wrote: > > On Thu, Jun 29, 2017 at 12:47:10PM +0200, Dimitry Andric wrote: >> One nasty problem with this is that it is not possible to figure out at >> compile time what the size of time_t is. You always need some sort of >> configure-time test, and an external define. > > It is arguably possible, with constexpr.
I took Dimitry's wording as probably referring to testing the size in the C/C++ preprocessor like the original code tests for __LP64__ being defined vs. not to control what it does: extending that to involve more preprocessor tests to pick from more code blocks. (But it is a guess given his wording.) I also took him to be excluding C++17's if-constexpr (or that the limitations in where how it can be used would prevent his intent) --and excluding the types of meta-programming/Substitution-Failure-Is-Not-An-Error usage that if-constexpr can simplify: too much rework of parts of libc++. Net result: extending the Makefile's "if" that he referenced with a powerpc-family test removes something in more contexts than have the problem. I think that he was wishing for a simple way to avoid that loss but still prevent the problem cases. === Mark Millard markmi at dsl-only.net _______________________________________________ freebsd-current@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
