On Wed, Dec 06, 2023 at 02:34:10PM +0100, Martin Uecker wrote:
> > Further I think
> > "size less than or equal to the size requested"
> > is quite ambiguous in the calloc case, isn't the size requested in the
> > calloc case actually nmemb * size rather than just size?
>
> This is unclear but it can be understood this way.
> This was also Joseph's point.
>
> I am happy to submit a patch that changes the code so
> that the swapped arguments to calloc do not cause a warning
> anymore.
That would be my preference because then the allocation size is
correct and it is purely a style warning.
It doesn't follow how the warning is described:
"Warn about calls to allocation functions decorated with attribute
@code{alloc_size} that specify insufficient size for the target type of
the pointer the result is assigned to"
when the size is certainly sufficient.
But wonder what others think about it.
BTW, shouldn't the warning be for C++ as well? Sure, I know,
people use operator new more often, but still, the <cstdlib>
allocators are used in there as well.
We have the -Wmemset-transposed-args warning, couldn't we
have a similar one for calloc, and perhaps do it solely in
the case where one uses sizeof of the type used in the cast
pointer?
So warn for
(struct S *) calloc (sizeof (struct S), 1)
or
(struct S *) calloc (sizeof (struct S), n)
but not for
(struct S *) calloc (4, 15)
or
(struct S *) calloc (sizeof (struct T), 1)
or similar? Of course check for compatible types of TYPE_MAIN_VARIANTs.
Jakub
