Re: [PATCH 3/5] autoconf: Preliminary check for working mmap

> Junio C Hamano wrote:
> 
> > Jakub Narebski <jnareb@gmail.com> writes:
> > 
> >> This patch sent earlier in other patch series and dropped,
> >> as git uses private mapping, not private fixed. I think
> >> that this check is better than no check at all...
> > 
> > I think the next major change that is needed fairly soon is to
> > be able to mmap parts of a large pack file (even with 32-bit
> > offset).  I haven't loooked into it deeply enough but it may or
> > may not turn out to be beneficial if we map at fixed location so
> > the requirements of "working mmap()" might change.  I'd be
> > happier if you held onto this part of the patch before that
> > happens.
> 
> Well, this patch perhaps not always would set NO_MMAP when it should 
> (some broken mmap that does private+fixed but not private), but I guess that
> if it would set NO_MMAP then mmap is broken (or doesn't exist at all).
> 
> I have noticed AC_FUNC_MMAP test, and thought why not to use it?
> The simplest check if mmap exist would be to check libc for mmap function.