On Wed, Jan 09, 2019 at 11:15:58AM -0800, Linus Torvalds wrote:
> On Wed, Jan 9, 2019 at 11:01 AM Ramsay Jones
> <ramsay@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Ahem, so yes, both gcc and clang allow this (I just tested it), but
> > my reading of the C99 standard lead me to believe that this is not
> > valid C. (Not that it really matters).
>
> Interesting. Looking at the kernel, we actually have a lot of them, ie
>
> [torvalds@i7 linux]$ git grep 'struct.*= {[:space:]*}' | wc
> 1105 6766 81616
>
> although admittedly we also have a fair amount of the { 0 } kind:
>
> [torvalds@i7 linux]$ git grep 'struct.*= {[:space:]*0[:space:]*}' | wc
> 616 3722 50034
Happily, in a x86-64 defconfig + allyesconfig, there is only 120
"Using plain integer as NULL pointer" warnings and not all of them
are because of this { 0 }.
But this make me wonder ...
I'm all for strict typing, it's in general a precious help, but
for this "Using plain integer as NULL pointer" warning:
1) the problem of using 0 (an int) in a variadic function call
expecting a pointer (possibly larger than an int) is well known
but is there any other problem of using 0 instead of NULL?
2) when the warning is issued it is known that a pointer is expected
so a size problem like in 1) is not possible.
So isn't this a case of a 'bad warning'?
Maybe sarse should relax this warning, maybe only in (compound)
initializer? [issuing a warning
when passing 0 to a variadic function should address problem 1)
but would probably create a lot of false warnings too].
-- Luc
