Re: Obsolete and Removed POSIX Functions

[Joel Sherrill <joel dot sherrill at oarcorp dot com>]

On 2/15/2016 1:21 PM, Yaakov Selkowitz wrote:
> On 2016-02-15 13:09, Joel Sherrill wrote:
> > I am unsure how methods noted by POSIX as obsolete should
> > be guarded.
> >
> > http://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_xsh_chap01.html
> >
> > For example, asctime() and asctime_r() were marked as obsolescent
> > in Issue 7.
>
> obsolete != removed:
>
> http://man7.org/linux/man-pages/man3/asctime.3.html

Agreed. But an aggressive approach would be to warn users
and recommend changes. Obsolete is the first step on the
path to removal.

If I had working code that used an obsolete methods, I
wouldn't read a man page to see that I used a methods which
was on the way out. I wouldn't notice this unless I was lucky
or writing new code.

Just wondering if there is a possibility of an action that
is helpful to users.

> > Similarly, that page lists some methods that should be removed.
> > I am assuming it is OK to still support them but what should the
> > guards be?
>
> Did you see my RFC:
>
> https://sourceware.org/ml/newlib/2016/msg00072.html
>
> There are several examples therein, which can easily be found by
> searching for "&& !__"

I looked through there and using bcmp() as an example...

-#if __BSD_VISIBLE
+#if __BSD_VISIBLE || (__POSIX_VISIBLE && !__POSIX2008_VISIBLE)
 int	 _EXFUN(bcmp,(const void *, const void *, size_t));
 void	 _EXFUN(bcopy,(const void *, void *, size_t));
 void	 _EXFUN(bzero,(void *, size_t));
+#endif

Where is __POSIX2008_VISIBLE defined?

If POSIX 2013 is requested, then is bcmp() prototyped or not?
It is removed in 2013 and (I assume) obsolete in 2008.

I don't see the rationale for the ! portion.

And I see some CYGWIN conditions replaced with checks for
POSIX 2008. Is that an equivalent check? fexecve() is a
very simple example and AT_FDCWD has a more complicated
conditional.

ucontext.h methods are removed in Issue 7 so I wonder if
the check around <sys/ucontext.h> is right.

The 2013 question may not be fair because I doubt newlib
has been reviewed at all for that. But that's the change
boundary I am looking at.


--joel