change log for rtems (2011-02-24)

Gedare Bloom gedare at
Fri Feb 25 17:52:39 UTC 2011

On Fri, Feb 25, 2011 at 11:13 AM, Ralf Corsepius
<ralf.corsepius at> wrote:
> On 02/25/2011 12:26 PM, Chris Johns wrote:
>> On 25/02/11 9:25 PM, Ralf Corsepius wrote:
>>> And I don't share this view and fail to understand why you and Chris are
>>> complaining.
>> I was not complaining. Rather I was just understanding the reason so I
>> can determine if I need to be doing something more when I add code like
>> this in the future.
> As I tried to explain before, it's
> * in first place "code clarity" (e.g. when grepping the code when going
> after questions like "where is the declaration/definion", what may be the
> cause of the symbol-clash, what is the reason for this "cryptic linker
> error" etc.)
Not really, because it is common for the non-extern declaration
(prototype) to be in a header file, e.g. statvfs.h, and the associated
definition (body) to be in a C file, e.g. statvfs.c. Seeing it
declared extern in a header file would make me think it is in some
other file "namespace" so to speak.

> and
> * in second place avoiding conflicts (e.g. when a file contains a local
> "static foo()" and misses to include the global header, when the global
> header wants "extern foo()", ...).
Not sure I understand the example/use case you propose. If the header
is missed, it doesn't matter how the function is declared. If the
header is included, it will complain that the static definition
follows non-static declaration. I just don't see any savings here for
avoiding conflicts. Maybe if you can give a concise and reasonable
example for why this change affects correctness the argument will go

> Another (hardly relevant to RTEMS) issue would be interfacing with C++,
> which implictily treats functions without "extern" (and without "extern C")
> as static.
Well, since we already have to wrap all headers with extern C, this is
a non-issue.

I don't really agree with the convention that all headers should
declare all functions as extern, but it should be decided one way or
another to prevent future confusion on whether it is a convention or
not.  This does seem like a "whitespace" type of issue, since it does
not AFAIK affect any program correctness.

> Ralf
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