On Tue, Oct 04, 2016 at 06:08:33PM +0200, Johannes Schindelin wrote: > Hi Rich, > > On Tue, 4 Oct 2016, Rich Felker wrote: > > > On Tue, Oct 04, 2016 at 11:27:22AM -0400, Jeff King wrote: > > > On Tue, Oct 04, 2016 at 11:08:48AM -0400, Rich Felker wrote: > > > > > > > 1. is nonzero mod page size, it just works; the remainder of the last > > > > page reads as zero bytes when mmapped. > > > > > > Is that a portable assumption? > > > > Yes. > > No, it is not. You quote POSIX, but the matter of the fact is that we use > a subset of POSIX in order to be able to keep things running on Windows. > > And quite honestly, there are lots of reasons to keep things running on > Windows, and even to favor Windows support over musl support. Over four > million reasons: the Git for Windows users. > > So rather than getting into an ideological discussion about "broken" > systems, it would be good to keep things practical, realizing that those > users make up a very real chunk of all of Git's users. > > As to making NO_REGEX conditional on REG_STARTEND: you are talking about > apples and oranges here. NO_REGEX is a Makefile flag, while REG_STARTEND > is a C preprocessor macro. It seems like you could just always compile the source file, and just have it all inside #if defined(NO_REGEX) || !defined(REG_STARTEND) or similar. > And lastly, the best alternative would be to teach musl about > REG_STARTEND, as it is rather useful a feature. Maybe, but it seems fundamentally costly to support -- it's extra state in the inner loops that imposes costly spill/reload on archs with too few registers (x86). I'll look at doing this when we overhaul/replace the regex implementation, and I'm happy to do some performance-regression tests for adding it now if someone has a simple patch (as was mentioned on the musl list). Rich