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From: John Nagle <nagle@animats.com>
Newsgroups: comp.std.c
Subject: Second draft, "Safe arrays and pointers for C"
Date: Thu, 30 Aug 2012 12:48:15 -0700
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In response to all the comments above under "Initial draft proposal:
"Safe arrays and pointers for C", I have a new revision for
discussion.

http://www.animats.com/papers/languages/safearraysforc41.pdf

Major changes:

- It's made clearer that non-strict code can call strict code
  and vice versa, and that function prototypes can be written
  in strict style and called from both strict code (with
  checking) and non-strict code (without checking).  Thus,
  there's a clear migration path to strict code - start
  with the low level libraries and work up.

- The proposed generic functions have been removed. Instead,
  it is proposed to import the "decltype" feature from C++.
  This allows writing the generic functions needed for
  making "malloc" allocation type-safe as C macros.

- The proposal is written relative to N1570.

- Run time subscript and size checking action is
  as specified in N1570, Annex K.

- The relationship with C variable length arrays is discussed.

- The problem of forward-referenced formal parameters
  (where the declaration of an array is followed by
  a parameter with its size) is addressed, using the
  GCC forward declaration extension.

- The restrictions on array length expressions needed
  for consistency between call and definition are made
  explicit.

- Implications for this feature in C++ are briefly discussed,
  the intent being to avoid divergence from C++.  The issue of
  how C++ style "name mangling" and variable length array
  parameters could coexist is addressed.  This
  proposal is now potentially compatible with C++ as
  well as C.

Please comment, as before.  I would particularly like to hear
from people involved with GCC as to how difficult a job it
would be to implement this in GCC as an extension.  Then
we could get some experience with this approach.

				John Nagle