Re: Union padding

From:

Pete Becker <pete@versatilecoding.com>

Newsgroups:

comp.lang.c++.moderated

Date:

Mon, 30 Apr 2012 21:35:01 -0700 (PDT)

Message-ID:

<2012043018504613254-pete@versatilecodingcom>

On 2012-04-30 22:42:57 +0000, red floyd said:

On 4/30/2012 1:08 PM, Daryle Walker wrote:

I've been testing out types like:

union
{
T1 a;
T2 b;
union
{
T3 ca;
T4 cb;
} c;
} d;

[redacted]
Looking at Section 9.5 Paragraph 1 in the copy of C++11 I just
bought, and it seems that my desired behavior isn't guaranteed.
There may be padding between the start of the union and any of its
members, and the padding for each member may differ. Am I accurate
in this assessment?

From N3242. 9.5/5 The final sentence of the example implicitly
notes that union members all have the same address. I'm not sure if
this is normative or not.

Examples and notes are not normative.

--
   Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The
Standard C++ Library Extensions: a Tutorial and Reference
(www.petebecker.com/tr1book)

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