Re: [Qemu-devel] [PATCH 3/8] 9pfs: fix P9_NOTAG and P9_NOFID macros

[Eric Blake]

On 12/09/2016 03:28 AM, Greg Kurz wrote:
> The u16 and u32 types don't exist in QEMU common headers. It never broke
> build because these two macros aren't use by the current code, but this
> is about to change with the future addition of functional tests for 9P.
> 
> This patch convert the types to uintXX_t.
> 
> Signed-off-by: Greg Kurz <address@hidden>
> ---
>  hw/9pfs/9p.h |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
> index 3976b7fe3dcd..89c904bdb7e7 100644
> --- a/hw/9pfs/9p.h
> +++ b/hw/9pfs/9p.h
> @@ -99,8 +99,8 @@ enum p9_proto_version {
>      V9FS_PROTO_2000L = 0x02,
>  };
>  
> -#define P9_NOTAG    (u16)(~0)
> -#define P9_NOFID    (u32)(~0)
> +#define P9_NOTAG    (uint16_t)(~0)
> +#define P9_NOFID    (uint32_t)(~0)

Don't you want to write ((uint16_t)(~0)), to ensure that this expression
can be used as a drop-in in any other syntactical situation?

Or even write it as UINT16_C(~0) (using <stdint.h>), or as UINT16_MAX.
(Be aware: the type of (uint16_t)(~0) is uint16_t, while the type of
UINT16_MAX is int, due to the rules of integer promotion, if that matters)

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

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