Re: [PATCH] mbsstr: fix warnings reported by gcc -Wcast-align on ARM

[Bruno Haible]

Hi,

Dmitry V. Levin wrote:
> * lib/mbsstr.c (knuth_morris_pratt_multibyte): Assign a raw memory
> pointer returned by nmalloca() right to the variable of type
> "mbchar_t *" thus removing redundant proxy variable of type "char *".

Thanks for the patch, but I don't feel that it is an improvement over the
existing code: it makes the code harder to understand.
I allocate a variable 'memory' that contains both 'needle_mbchars' and
'table'. When I call free(memory), it is clear that both are freed.
Whereas in your rewrite, 'table' becomes an backpack on 'needle_mbchars',
and when you write free(needle_mbchars), one keeps wondering why there
is no free(table).

> mbsstr.c:50: error: cast increases required alignment of target type 
> [-Wcast-align]

How is one supposed to write address computations needed for dissecting
a memory block into several memory blocks, when this warning is enabled?
With 'void *' I cannot do address arithmetic. With 'char *' I get these
warnings. 'uintptr_t'? Berk, no.

In summary, please turn off -Werror when compiling gnulib code. We don't
guarantee the absence of warnings.

Bruno