Re: extern const initialized warns in C

[Jonathan Wakely <jwakely.gcc@gmail.com>]

On 25 January 2018 at 12:27, Georg-Johann Lay wrote:
> On 22.01.2018 16:20, Jonathan Wakely wrote:
>>
>> On 21 January 2018 at 12:08, Georg-Johann Lay wrote:
>>>
>>> Jay K schrieb:
>>>>
>>>>
>>>> extern const int foo = 123;
>>>>
>>>> Why does this warn?
>>>> This is a valid portable form, with the same meaning
>>>> across all compilers, and, importantly, portably
>>>> to C and C++.
>>>
>>>
>>> I also wondered about this.
>>>
>>> In C99 §6.9.2 "External object definitions" there's actually
>>> the following example in clause 4:
>>>
>>> extern int i3 = 3; // definition, external linkage
>>
>>
>> That's a different case. There's no advantage to the 'extern' here,
>> because the code means the same thing in C and C++ without the
>> 'extern', so just leave it out.
>
>
> I'd rather like to know why GCC is throwing a warning here.
>
> It's clear how to hack the C source, but that's a different point.
>
> It's just the case that I don't see any problem with that construct,
> and it was worth an explicit example in the standard.  Or is it
> common practice to warn constructs that are "no advantage"?

Read https://gcc.gnu.org/bugzilla/show_bug.cgi?id=45977 (as already
stated earlier in the thread).