Re: [PATCH 0/9] MISRA C 2012 8.1 rule fixes

[Roberto Bagnara <roberto.bagnara@bugseng.com>]

Hi Jan.

I know I will sound pedantic ;-)  but an important fact about
the MISRA standards is that reading the headline alone is almost
never enough.  In the specific of (advisory) Directive 4.6,
the Rationale says, among other things:

     It might be desirable not to apply this guideline when
     interfacing with The Standard Library or code outside
     the project’s control.

For this reason, size_t is typically set as an exception in the
tool configuration.  To properly deal with the many Standard Library
functions returning int, one can use a typedef named something
like "lib_int_t" to write, e.g.,

   const lib_int_t r = strncmp(...);

The lib_int_t typedef can be used with a suitable tool configuration,
just as I mentioned one would do with size_t.
Kind regards,

    Roberto

On 23/06/22 09:51, Jan Beulich wrote:
> On 23.06.2022 09:37, Roberto Bagnara wrote:
>> Rule 8.1 only applies to C90 code, as all the violating instances are
>> syntax errors in C99 and later versions of the language.  So,
>> the following line does not contain a violation of Rule 8.1:
>>
>>       unsigned x;
>>
>> It does contain a violation of Directive 4.6, though, whose correct
>> handling depends on the intention (uint32_t, uin64_t, size_t, ...).
> 
> Interesting - this goes straight against a rule we have set in
> ./CODING_STYLE. I'm also puzzled by you including size_t in your list
> of examples, when the spec doesn't. The sole "goal" of the directive
> (which is advisory only anyway) is to be able to determine allocation
> size. size_t size, however, varies as much as short, int, long, etc
> do.
> 
> Jan