Re: diffseq: Silence gcc warning

[Paul Eggert]

On 2023-05-27 09:25, Bruno Haible wrote:
> For 30 years, "gcc -Wall" has been and is the best recipe
> for getting meaningful warnings across packages. It's not like a
> "random compiler".

It can be a random compiler if you use GCC the wrong way. If you use an 
old version of GCC it might generate bogus diagnostics. Or if you 
combine -Wall with some other options (-mx32, -Og, etc.) it might 
generate bogus diagnostics. We shouldn't waste time pacifying gcc on 
every possible platform with every possible set of options (each of 
which is in effect a new platform), especially when this pacification 
might create false negatives.

For programs like diffutils that use the manywarnings module, the best 
way to generate warnings is to configure with --enable-gcc-warnings. If 
there are other ways to generate warnings to find bugs that are worth 
the trouble of pacifying GCC, then it'd be helpful to use those ways 
too. But plain 'gcc -Wall' is not one of those ways.

> But when gcc 14 is released, with new warning
> options in -Wall and possibly regressions, some new workarounds may be
> needed.

Yes, and this is a normal course of affairs. I routinely do that with 
each GCC release, and update the manywarnings module accordingly. This 
process works well, for programs that use that module. It works better 
than gcc -Wall does, in my experience.