Re: lib/53640: getnstr(3) shall read at most n characters, not n-1

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

The following reply was made to PR lib/53640; it has been noted by GNATS.

From: Valery Ushakov <uwe%stderr.spb.ru@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: lib/53640: getnstr(3) shall read at most n characters, not n-1
Date: Fri, 22 Mar 2019 00:41:40 +0300

 On Sat, Sep 29, 2018 at 18:29:35 +0300, Valery Ushakov wrote:
 
 > On Sat, Sep 29, 2018 at 14:05:00 +0000, Kamil Rytarowski wrote:
 > 
 > >  >  On Sat, Sep 29, 2018 at 10:30:01 +0000, n54%gmx.com@localhost wrote:
 > >  >
 > >  >  > It's documented in POSIX to reat at most N bytes; but the NetBSD
 > >  >  > curses(3) version reads at most N-1 bytes.
 > >  >  >
 > >  >  > http://pubs.opengroup.org/onlinepubs/7908799/xcurses/getnstr.html
 [...]
 > Given the overall confusion that usually surrounds these kinds of "n"
 > functions, it would be better that this kind of details is specified
 > as explicitly as possible.
 [...]
 > As I said in my previous reply, all manual pages for this suck in one
 > way or another and I still think NetBSD behavior seems globally
 > correct (POSIX wording notwithstanding).
 
 Just for the record.  X/Open Curses, Issue 7 says:
 
   The getnstr(), mvgetnstr(), mvwgetnstr(), and wgetnstr() functions
   are equivalent to the getstr(), mvgetstr(), mvwgetstr(), and
   wgetstr() functions respectively, except that they read at most N-1
   bytes, thus preventing a possible overflow of the input buffer.
 
 Note N-1
 
 -uwe