Re: [PATCH 1/7] Rework strbuf API and semantics.

Jeff King [off-list ref] writes:

On Thu, Sep 06, 2007 at 05:06:52PM +0200, David Kastrup wrote:

quoted

quoted

  If an object that has automatic storage duration is not initialized
  explicitly, its value is indeterminate. If an object that has static
  storage duration is not initialized explicitly, then:

  -- if it has pointer type, it is initialized to a null pointer;

That's actually a new one to me.  I don't think that it has been
always the case in ANSI C.

I don't have the C89 standard, so it's hard to be authoritative.
However, according to TCOR1 to the C89 standard, the original text of
6.5.7 contained:

  If an object that has static storage duration is not initialized
  explicitly, it is initialized implicitly as if every member that has
  arithmetic type were assigned 0 and every member that has pointer type
  were assigned a null pointer constant.

Maybe I am confusing this with the effects of calloc or memset(...,0).

But for the case of pointer initializations, both have the same
effect.  So I think it has always been the case. Pre-ANSI, who
knows. :)

In the original K&R C, a null pointer likely could have been assumed
to have zero bits throughout.  The non-zero-bits NULL pointer concept
just reeks of standard committees...  So maybe this never had been an
issue, for different reasons.

And now I must go get some real work done instead of snooping
through standards. :)

Sorry for the diversion.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum