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Postings from April 2014
On 04/27/2014 02:11 PM, Jarkko Hietaniemi wrote:
> On Sunday-201404-27, 15:57, Craig A. Berry wrote:
>> It's complaining about the return value, which we're doing our best to
>> throw away and thereby emulate a void gconvert:
>
> I am confused: what's wrong with (void)?
>
>> http://perl5.git.perl.org/perl.git/blobdiff/04783dc7025287c5d75ab531602c7ec786a1e787..cca0492ec62cab786a01ea96c47e549fe0aa8c61:/sv.c
>>
>
> "void Gconvert: on Linux at least, gcvt (which Gconvert gets deffed
> to),has a mandatory return value" - how "mandatory" are we talking about?
>
>> I don't think it's doing any real harm, but warnings that need to be
>> ignored tend to accumulate and then it's too easy to ignore all
>> warnings.
>
> Indeed.
>
Actually, there is another way to handle these warnings that hadn't been
put into Perl at the time this commit was made. These lines in perl.h
describe it
======================
/* on gcc (and clang), specify that a warning should be temporarily
* ignored; e.g.
*
* GCC_DIAG_IGNORE(-Wmultichar);
* char b = 'ab';
* GCC_DIAG_RESTORE;
*
* based on http://dbp-consulting.com/tutorials/SuppressingGCCWarnings.html
*
* Note that "pragma GCC diagnostic push/pop" was added in GCC 4.6, Mar
2011;
* clang only pretends to be GCC 4.2, but still supports push/pop.
*/
#if defined(__clang) || \
(defined( __GNUC__) && ((__GNUC__ * 100) + __GNUC_MINOR__) >= 406)
# define GCC_DIAG_DO_PRAGMA_(x) _Pragma (#x)
# define GCC_DIAG_IGNORE(x) _Pragma("GCC diagnostic push") \
GCC_DIAG_DO_PRAGMA_(GCC diagnostic ignored #x)
# define GCC_DIAG_RESTORE _Pragma("GCC diagnostic pop")
#else
# define GCC_DIAG_IGNORE(w)
# define GCC_DIAG_RESTORE
#endif
======================
And I used it for this particular warning in locale.c
GCC_DIAG_IGNORE(-Wunused-result);
(void) mbtowc(&wc, NULL, 0); /* Reset any shift state */
GCC_DIAG_RESTORE;
I think this is preferable to the current V_Gconvert solution
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