Re: [PATCH 0/5] obstacks again

[Paul Eggert <eggert at cs dot ucla dot edu>]

On 10/29/2014 11:07 PM, Alan Modra wrote:
> So there are my reasons for leaving obstack_blank as is.

Thanks, they're persuasive.  With that in mind, I have a minor complaint 
about obstack_blank_fast's revised documentation.  It says "You can use 
@code{obstack_blank_fast} with a negative size argument to make the 
current object smaller."  Technically, though, the argument is of type 
size_t so it cannot be negative.  So, how about if we change this 
wording to "If @var{S} is a positive size, you can give 
@code{obstack_blank_fast} a ``negated'' (actually, large positive) size 
@code{-@var{S}} to shrink the current object by @var{S} bytes."  Also, 
it may be worth noting explicitly that this trick does not work for 
object_blank.

Also, doesn't libc need a NEWS item for these changes?  At least, gnulib 
needs one; I installed the attached.

> Oh, and while I'm advocating breakage, the doc for obstack_next_free
> says it returns a void* but actually returns a char*.  Since it was
> deemed a good idea to similarly correct obstack_base, should we do the
> same for obstack_next_free?

Yes, that makes sense.  Don't we have similar problems with lots of 
other macros and/or functions: obstack_1grow_fast, obstack_blank_fast, 
obstack_int_grow, etc.?  They all seem to return types that don't match 
the documentation.  As long as we're fixing things, this might all be 
done in a separate patch.

> It's missing @safety markup for the
> previously undocumented obstack_begin, obstack_specify_allocation, and
> obstack_specify_allocation_with_arg macros.  I'm hoping someone else
> can do that as I'd just be guessing.  (Are they even appropriate for
> macros?)

Sorry, I don't know.

If I understand the recent set of proposed patches correctly, no further 
changes need to be made to gnulib, unless we decide to go ahead with the 
further "breakage" mentioned above.
>From 049f337efd051bc4821173844fc9a5fdd38fb51a Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Fri, 31 Oct 2014 12:45:22 -0700
Subject: [PATCH] obstack: add NEWS entry for recent incompatible changes

* NEWS: Describe recent changes.
---
 ChangeLog |  5 +++++
 NEWS      | 10 +++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/ChangeLog b/ChangeLog
index 0d6c285..1f80f39 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2014-10-31  Paul Eggert  <eggert@cs.ucla.edu>
+
+	obstack: add NEWS entry for recent incompatible changes
+	* NEWS: Describe recent changes.
+
 2014-10-30  Pádraig Brady  <P@draigBrady.com>
 
 	mountlist: don't use libmount to decide on dummy/remote
diff --git a/NEWS b/NEWS
index 45d829b..23dd4f1 100644
--- a/NEWS
+++ b/NEWS
@@ -32,8 +32,16 @@ User visible incompatible changes
 
 Date        Modules         Changes
 
+2014-10-29  obstack         The obstack functions are no longer limited to
+                            int sizes; size values are now of type size_t.
+                            This changes both the ABI and the API.
+                            obstack_blank no longer accepts a negative size to
+                            shrink the current object; callers must now use
+                            obstack_blank_fast with a "negative" (actually,
+                            large positive) size for that.
+
 2014-02-23  diffseq         The members too_expensive, lo_minimal and hi_minimal
-                            were removed from public structureas, and the
+                            were removed from public structures, and the
                             find_minimal argument was removed from diag
                             and compareseq.
 
-- 
1.9.3