Re: [Qemu-devel] [PATCH] linux-user: Remove type casts to union type

[Michael Tokarev <mjt@tls.msk.ru>]

08.02.2015 17:40, Stefan Weil wrote:
> Casting to a union type is a gcc (and clang) extension. Other compilers
> might not support it. This is not a problem today, but the type casts
> can be removed easily. Smatch now no longer complains like before:
> 
> linux-user/syscall.c:3190:18: warning: cast to non-scalar
> linux-user/syscall.c:7348:44: warning: cast to non-scalar
> 
> Cc: Riku Voipio <riku.voipio@iki.fi>
> Signed-off-by: Stefan Weil <sw@weilnetz.de>
> ---
>  linux-user/syscall.c |   10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 852308e..ec137db 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -2663,8 +2663,9 @@ static inline abi_long host_to_target_semarray(int semid, abi_ulong target_addr,
>  }
>  
>  static inline abi_long do_semctl(int semid, int semnum, int cmd,
> -                                 union target_semun target_su)
> +                                 abi_ulong target_arg)
>  {
> +    union target_semun target_su;
>      union semun arg;
>      struct semid_ds dsarg;
>      unsigned short *array = NULL;
> @@ -2673,6 +2674,8 @@ static inline abi_long do_semctl(int semid, int semnum, int cmd,
>      abi_long err;
>      cmd &= 0xff;
>  
> +    target_su.buf = target_arg;


Can we use c99 initializers at declaration, something like

   union target_semun target_su = { .buf = target_arg }

?  Or is it also some gcc/clang extension? :)

But I'd like to hear from Riku at least...

Thanks,

/mjt