Re: [whish] -Wunterminated-string-initialization: new warning

[Alejandro Colomar <alx.manpages@gmail.com>]

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Hi Jonathan,

On 11/14/22 14:14, Jonathan Wakely wrote:
> On Mon, 14 Nov 2022 at 11:38, Alejandro Colomar via Gcc <gcc@gcc.gnu.org> wrote:
>>
>> Hi Andrew!
>>
>> On 11/13/22 23:12, Andrew Pinski wrote:
>>> On Sun, Nov 13, 2022 at 1:57 PM Alejandro Colomar via Gcc
>>> <gcc@gcc.gnu.org> wrote:
>>>>
>>>> Hi!
>>>>
>>>> I'd like to get warnings if I write the following code:
>>>>
>>>> char foo[3] = "foo";
>>>
>>> This should be easy to add as it is already part of the -Wc++-compat
>>> option as for C++ it is invalid code.
>>>
>>> <source>:2:19: warning: initializer-string for array of 'char' is too long
>>>       2 | char     two[2] = "foo";   // 'f' 'o'
>>>         |                   ^~~~~
>>> <source>:3:19: warning: initializer-string for array of 'char' is too
>>> long for C++ [-Wc++-compat]
>>>       3 | char   three[3] = "foo";   // 'f' 'o' 'o'
>>>         |                   ^~~~~
>>>
>>>
>>> ... (for your more complex case [though I needed to modify one of the
>>> strings to exactly 8]
>>>
>>> <source>:5:7: warning: initializer-string for array of 'char' is too
>>> long for C++ [-Wc++-compat]
>>>       5 |       "01234567",
>>>         |       ^~~~~~~~~~
>>>
>>>                 else if (warn_cxx_compat
>>>                          && compare_tree_int (TYPE_SIZE_UNIT (type), len) < 0)
>>>                   warning_at (init_loc, OPT_Wc___compat,
>>>                               ("initializer-string for array of %qT "
>>>                                "is too long for C++"), typ1);
>>>
>>> That is the current code which does this warning even so it is just a
>>> matter of adding an option to c-family/c.opt and then having
>>> c++-compat enable it and using that new option here.
>>>
>>> Thanks,
>>> Andrew Pinski
>>
>> Great!  I'd like to implement it myself, as I've never written any GCC code yet,
>> so it's interesting to me.  If you recall any (hopefully recent) case where a
>> similar thing happened (the warning was already implemented and only needed a
>> name), it might help me check how it was done.
> 
> `git log gcc/c-family/c.opt` will show loads of changes adding warnings.

Thanks, I will check and try it, and come back if I have any doubts.

Cheers,

Alex

-- 
<http://www.alejandro-colomar.es/>

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