Consensus on MT-, AS- and AC-Safety docs.

[Joseph S. Myers]

On Fri, 22 Nov 2013, Alexandre Oliva wrote:

> > I prefer longer, more readable names (e.g. floating-point-environment).
> 
> But that's meaningless.  Well, yeah, I understand

It names the state used by the function.

> We actually have good, settled precedent in using non-English keywords
> in error codes that may be stored in errno.

"I would have spelled creat with an 'e'.".  Overly short existing names 
aren't really a good example to follow....

> potential of stream uses et al in there.  If I had to guess (and I do
> :-) I'd say it was because I remember that this was all deprecated (I
> vaguely recall reading some email about that not too long ago), or I
> mistook _LIB_VERSION as a constant and from that misconcluded the code
> in question would have been optimized away or never executed (I can't
> rule out this possibility).
> 
> Anyway...  What now?  Should the manual even mention this caveat when it
> doesn't seem to document the deprecated feature at all?

While I'd quite like to deprecate this functionality and even get the 
_LIB_VERSION checks completely out of the runtime code paths for normal 
calls to libm functions from new binaries, the manual does document 
matherr:

  @findex matherr
  In the System V math library, the user-defined function @code{matherr}
  is called when certain exceptions occur inside math library functions.
  However, the Unix98 standard deprecates this interface.  We support it
  for historical compatibility, but recommend that you do not use it in
  new programs.

It just doesn't mention the need to set _LIB_VERSION (the matherr manpage 
does mention that).  (There's a single testcase for this, 
math/test-matherr.c.)

-- 
Joseph S. Myers
joseph@codesourcery.com