On Wed, Oct 17, 2012 at 09:06:23AM +0200, Otto Moerbeek wrote: > > Op 16 okt. 2012 om 22:56 heeft Jason McIntyre <j...@kerhand.co.uk> het > volgende geschreven: > > > On Sat, Oct 06, 2012 at 09:40:23PM +0200, Dawe wrote: > >> I think this information is already given in the sentences before. > >> > >> Index: mmap.2 > >> =================================================================== > >> RCS file: /cvs/src/lib/libc/sys/mmap.2,v > >> retrieving revision 1.39 > >> diff -u -p -u -p -r1.39 mmap.2 > >> --- mmap.2 12 Apr 2012 12:53:27 -0000 1.39 > >> +++ mmap.2 6 Oct 2012 19:35:32 -0000 > >> @@ -188,10 +188,6 @@ The symbol > >> .Dv MAP_FAILED > >> is defined in the header > >> .Ao Pa sys/mman.h Ac . > >> -No successful return from > >> -.Fn mmap > >> -will return the value > >> -.Dv MAP_FAILED . > >> .Sh ERRORS > >> .Fn mmap > >> will fail if: > >> > > > > philip guenther replied to this: > > > > No, it isn't. The previous sentences say that MAP_FAILED > > is returned on error; this one says that MAP_FAILED is > > *only* returned on error. Contrast this to strtoul(), where > > ULONG_MAX is returned on error, but can also be returned > > on success, meaning you have to do extra steps (clear errno > > before, test it afterwards) to detect failure. This sentence > > is the one that makes it clear that that isn't the case > > with mmap(). > > > > i have to say, i didn;t get that. after discussing it a bit i've come to > > see there is an ambiguity in the sentence being proposed for removal - it > > can be read two ways. > > Wondering which two ways. I can only see one. It must be either lack of > coffee or too much exposure to formal logic. > > That said, I like your diff. > > -Otto >
well, i spent a few days arguing with guenther before i saw it. so i'd say it's subtle ;) the sentence in question is this: No successful return from mmap will return the value MAP_FAILED. what it's trying to say is that "under no cicumstances will a successful mmap return MAP_FAILED". however i (and the original poster, i presume) read it as "an unsuccessful return from mmap will return MAP_FAILED". since the latter had already been said, we supposed it to be duplication. i'd have zapped it if guenther hadn;t spotted the true intent. jmc