Re: Removing -Wunsuffixed-float-constants, -Wdouble-promotion, -Wformat-zero-length

[Simon Josefsson]

Jim Meyering <address@hidden> writes:

> Paul Eggert wrote:
>> On 11/30/11 02:25, Jim Meyering wrote:
>>> how about automating the extraction of the list of
>>> warnings from gcc sources or from some web page
>>
>> Or perhaps extract it from the gcc executable
>> itself?  Then you'd get all the warnings that the
>> current GCC supports.
>
> Hah!
>
> I didn't know about --help=warnings.
> That looks perfect.
>
> For a quick and dirty comparison, I did this:
> (using gcc 4.7.0 20111124)
>
> diff -u \
>   <(sed -n 's/^  *\(-[^ ]*\) .*/\1/p' /gnulib/m4/manywarnings.m4 |sort) \
>   <(gcc --help=warnings|sed -n 's/^  \(-[^ ]*\) .*/\1/p' |sort)
>
> which shows at least one false positive (i.e. -Wformat=2 vs -Wformat=)
> and many new warnings:

Many of the new ones you list are for non-C.  The -Wformat=2 should be
correct, I believe the gcc --help=warnings output is incorrect?
-Wformat is implied by -Wall but -Wformat=2 adds more.

The --all-warnings and --extra-warnings are interesting, they were not
present when manywarnings.m4 was created.  I wonder how they work.

/Simon