Re: [Qemu-devel] [PATCH v2 01/12] host-utils: add ffsl

[Peter Maydell]

On 16 January 2013 17:31, Paolo Bonzini <address@hidden> wrote:
> We can provide fast versions based on the other functions defined
> by host-utils.h.  Some care is required on glibc, which provides
> ffsl already.
>
> Signed-off-by: Paolo Bonzini <address@hidden>

Hi. This patch breaks compile on MacOS (and likely other BSDs):

  CC    qga/commands-posix.o
In file included from qga/commands-posix.c:22:
/Users/pm215/src/qemu/include/qemu/host-utils.h:248: error: static
declaration of ‘ffsl’ follows non-static declaration

(because BSD strings.h provides a system ffsl()).

> +/* glibc does not provide an inline version of ffsl, so always define
> + * ours.  We need to give it a different name, however.
> + */
> +#ifdef __GLIBC__
> +#define ffsl qemu_ffsl
> +#endif

Overriding a system function like this seems a bit brittle --
can't we either (a) always use the system version or (b)
always use a QEMU implementation?

Failing that, you probably need a configure test to check for
system ffsl().

thanks
-- PMM