Re: offsetof and XtOffsetOf

From: Date: Fri, 05 Jun 2015 14:45:30 +0000
Subject: Re: offsetof and XtOffsetOf
References: 1 2 3  Groups: php.internals 
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Levi Morrison wrote on 05/06/2015 14:58:

On Thu, Jun 4, 2015 at 11:58 PM, Joe Watkins <[email protected]> wrote:

Explained here: http://lxr.php.net/xref/PHP_TRUNK/main/php.h#415


On Fri, Jun 5, 2015 at 5:06 AM, Levi Morrison <[email protected]> wrote:

The macro offsetof is required by the C89 standard to be defined in
stddef.h and remains in newer standards. The macro XtOffsetOf is
non-standard that is as far as I can tell a part of the X Toolkit
Intrinsics or Xlib.

Does anyone know the reasons why we are using the non-standard macro
instead of the standard one?

Thanks, Joe. However, that code just explains why are macros are that
way. It doesn't justify the use of XtOffsetOf over offsetof, just how
the ifdefs were obtained.



If I read it right, it's just a polyfill - if offsetof is defined, XtOffsetOf is just made an alias of it on line 444.

Presumably, contra the standard, there are some implementations that don't (or didn't) define it.

Regards,
-- 
Rowan Collins
[IMSoP]

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